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Posts with #cisco switches - cisco firewall tag

Configuring VTP on a Cisco Switch

January 30 2012 , Written by Cisco & Cisco Router, Network Switch Published on #Cisco Switches - Cisco Firewall

During the early days of networking, it was difficult to implement VLANs across networks. Each VLAN was manually configured on each network switch. Managing a large switched network used to be a complicated tasks, VLAN trunking methods has helped to ease this problem.

 

 VLAN Trunking Protocol (VTP) is a Cisco Proprietary which basic aim is to manage all configured VLANs across a switched network.  VTP helps to propagate and maintain VLAN configurations consistency to other switches on the network.

 

VTP is a messaging protocol that uses layer 2 trunk frames to add, delete and rename VLANs on a single domain. It helps to centralize changes which are sent to other switches on the network.

 

A switch had to be configured in the role of a VTP server to manage your VLAN configuration on your network. The sever(s) will share VLAN information with other switches on the network which must use the same domain name.

 

VTP learns only normal-range VLANs (VLAN IDs 1 to 1005).

The primary role of VTP is to maintain VLAN configuration consistency across a network administration domain.

 

VTP stores VLAN configurations in the VLAN database called vlan.dat.

After a trunk is established between switches, VTP advertisement is exchanged between the switches. Both the server switch and client exchange and monitor advertisement from one another to ensure each has an accurate record of VLAN information. VTP advertisement will not be exchanged if the trunk between the switches is inactive.

 

 

In the diagram above, a trunk link is configured between switch S1, - VTP Server, S2 and S3 - VTP client. After a trunk is established between the switches, VTP summary advertisement is exchanged among the switches.

 

More Notes:

VTP Configuration Guidelines 

Follow these steps to configure a Cisco Catalyst switch to use VTP successfully:

 

VTP Server Switches 

i. Before you begin configuration, ensure that all of the switches are set to their default settings.

 

ii. Always reset the configuration revision number before installing a previously configured switch into a VTP domain. Not resetting the configuration revision number allows for potential disruption in the VLAN configuration across the rest of the switches in the VTP domain.

iii. Configure at least two VTP server switches in your network. Because only server switches can create, delete, and modify VLANs, you should make sure that you have one backup VTP server in case the primary VTP server becomes disabled. If all the switches in the network are configured in VTP client mode, you cannot create new VLANs on the network.

 

iv. Configure a VTP domain on the VTP server. Configuring the VTP domain on the first switch enables VTP to start advertising VLAN information. Other switches connected through trunk links receive the VTP domain information automatically through VTP advertisements.

 

v. If there is an existing VTP domain, make sure that you match the name exactly. VTP domain names are case-sensitive.

 

vi. If you are configuring a VTP password, ensure that the same password is set on all switches in the domain that need to be able to exchange VTP information. Switches without a password or with the wrong password reject VTP advertisements.

 

vii. Ensure that all switches are configured to use the same VTP protocol version. VTP version 1 is not compatible with VTP version 2. By default, Cisco Catalyst 2960 switches run version 1 but are capable of running version 2. When the VTP version is set to version 2, all version 2 capable switches in the domain auto configure to use version 2 through the VTP announcement process. Any version 1-only switches cannot participate in the VTP domain after that point.

 

viii. Create the VLAN after you have enabled VTP on the VTP server. VLANs created before you enable VTP are removed. Always ensure that trunk ports are configured to interconnect switches in a VTP domain. VTP information is only exchanged on trunk ports.

 

VTP Client Switches 

i. As on the VTP server switch, confirm that the default settings are present.

ii. Configure VTP client mode. Recall that the switch is not in VTP client mode by default. You have to configure this mode.

iii. Configure trunks. VTP works over trunk links.

iv. Connect to a VTP server. When you connect to a VTP server or another VTP-enabled switch, it takes a few moments for the various advertisements to make their way back and forth to the VTP server.

v. Verify VTP status. Before you begin configuring the access ports, confirm that the revision mode and number of VLANs have been updated.

vi. Configure access ports. When a switch is in VTP client mode, you cannot add new VLANs. You can only assign access ports to existing VLANs.

 

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How to Configure DHCP on a Cisco ASA 5505?

January 4 2012 , Written by Cisco & Cisco Router, Network Switch Published on #Cisco Switches - Cisco Firewall

Dynamic Host Configuration Protocol (DHCP) is a network application protocol used by devices (DHCP clients) to obtain configuration information for operation in an Internet Protocol network. This protocol reduces system administration workload, allowing devices to be added to the network with little or no manual intervention.

Configure-DHCP-on-a-Cisco-ASA-5505-copy-1.jpg

 

The diagram has the network topology. In this network the firewall is the gateway of the 10.16.74.0/24 network. Firewall and Servers will be excluded from the DHCP pool.

First step is to configure the inside (LAN) interface on the 10.16.74.0/24 network

FIREWALL(config)#interface Vlan1
FIREWALL(config-if)#nameif inside
FIREWALL(config-if)#security-level 100
FIREWALL(config-if)#ip address 10.16.74.1 255.255.255.0

Next assign the LAN ports for the correct VLAN in this case port 1 of firewall will be on VLAN 1

FIREWALL(config)#interface Ethernet0/1
FIREWALL(config-if)#switchport access vlan 1
FIREWALL(config-if)#no shut

Lastly, configure the dhcp range and assign it to an interface. Configure DNS servers, one internal and one external in case the internal fails. Enable DHCP on the inside interface

FIREWALL(config)#dhcpd address 10.16.74.15-10.16.74.35 inside
FIREWALL(config)#dhcpd dns 10.16.74.10 4.2.2.2
FIREWALL(config)#dhcpd enable inside

In order to see which devices are receiving DHCP from the firewall run the following command

FIREWALL(config)#sh dhcpd binding

IP address Hardware address Lease expiration Type

 

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How to Enable a Web Interface on a Cisco Catalyst?

January 3 2012 , Written by Cisco & Cisco Router, Network Switch Published on #Cisco Switches - Cisco Firewall

Cisco Catalyst switches include remote configuration options such as connecting through telnet, SSH and web interface. If you are configuring a Cisco Catalyst switch but are uncomfortable with the Cisco command line (CLI), enabling configuration access through a web browser is a logic choice.

 How to Enable a Web Interface on a Cisco Catalyst

Things You'll Need

a.  Cisco Catalyst switch with telnet access enabled

  1. Privileged Exec mode password
  2. Telnet access password
  3. IP address of the Cisco Catalyst switch
  4. Microsoft Windows computer with Microsoft telnet client software installed

 

Instructions to Enable a Web Interface on a Cisco Catalyst

1. Click the "Start" button, then click the "Run" box (Windows XP) or click the "Search" box (Windows 7 or Vista). Type "cmd" in the "Run" or "Search" box, and then press the "Enter" key. The command line window will appear.

 

2. Type "telnet x.x.x.x" and substitute the IP address of the Cisco Catalyst switch for the "x.x.x.x," and then press the "Enter" key.

 

3. Type the password when requested to connect to the Cisco Catalyst.

 

4. Type "enable" and press the "Enter" key. Type the Privileged Exec password when requested, and press the "Enter" key.

 

5. Type "config t" and press the "Enter" key.

 

6. Type "ip http server" and press the "Enter" key.

 

7. Type "end" and press the "Enter" key.

 

Related: Configuring a Catalyst 4500 Series Switch for Network Assistant Management

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Cisco Catalyst 4500 Switches, Key Features and Hot Models

December 28 2011 , Written by Cisco & Cisco Router, Network Switch Published on #Cisco Switches - Cisco Firewall

The Cisco Catalyst 4500 switch is a mid-range modular chassis network switch manufactured by Cisco Systems. A Cisco Catalyst 4500 comprises a chassis, power supplies, one or two supervisors, line cards and service modules.

Cisco-4500-series.jpg

 

The Cisco Catalyst 4500 Series includes two series of Catalyst chassis: The Classic and newly launched E-Series chassis. The Classic and E-Series Catalyst 4500 chassis come in four sizes: 3-slot (4503-E), 6-slot (4506-E), 7-slot (4507R+E/4507R-E), and 10-slot (4510R+E/4510R-E).

 

The Cisco Catalyst 4500 Series Switches enable borderless networks, providing high performance, mobile, and secure user experience through Layer 2-4 switching investments. It enables security, mobility, application performance, video, and energy savings over an infrastructure that supports resiliency, virtualization, and automation.

 

Cisco 4500 Series Switches provide borderless performance, scalability, and services with reduced total cost of ownership and superior investment protection.

 

Key features you need to be clear:

Performance and Density:

848 Gbps fabric with 48 Gbps per slot delivers a 2.6x increase in performance over previous generation

Industry’s highest PoEP port density with up to 240 ports of full 30 Watt PoEP

 

Application Performance:

Unprecedented layer 2 - 4 application visibility and control with Flexible NetFlow

Only modular access platform that can guarantee Service Level Agreements with IP SLA

 

Security:

Cisco TrustSec with 802.1ae (MACSec) hop-by-hop encryption and Security Group Tags (hardware-ready)

Anomaly and malware prevention through predefined, policy-based responses with Flexible NetFlow

 

Simplicity:

End-to-end campus deployment with single software release and common sparing

Complete Life Cycle Management: Design, Install, Operations and Upgrades

Simplified software licensing with a single image for LAN Base, IP base and Enterprise Services software

 

Operational efficiency:

In Service Software Upgrades for industry leading availability

Zero-touch, intelligent provisioning through Auto SmartPorts, AutoInstall and AutoQoS

Comprehensive automation with Cisco IOS Embedded Event Manager

Proactive diagnostics and remediation with Cisco Smart Call Home

Industry-leading power management with Cisco EnergyWise

 

Investment protection:

Backward and forward compatibility

Industry-leading investment protection with more than 10 years of backward compatibility

The benefits of Supervisor 7-E without line card upgrades

 

More details related to Cisco 4500 switches

Catalyst 4500 Line Cards

The Cisco Catalyst 4500 Series offers two classes of line cards: classic and E-Series. Classic line cards provide 6 gigabits of switching capacity per slot. E-Series line cards increase the per slot switching capacity to 24 gigabits.

 

Cisco 4500 switch power supplies

The Cisco 4500 is able to deliver high densities of Power over Ethernet across the chassis. Due to this, power supplies are a key element of configuration. The Cisco Catalyst 4500 E-Series offers AC power with several internal supplies: 1000W (data only), 1400W (data only), 1300W (data and PoE), 2800W (data and PoE), 4200W (data and PoE), and 6000W (data and PoE).

 

The Cisco Catalyst 4500 E-Series has two DC power options—one is optimized for data-only deployments in service provider central offices (part number PWR-C45-1400DC), and the other is used for high-power PoE deployments (PWR-C45-1400DC-P).

 

Operating systems

The Catalyst 4500 currently supports Cisco IOS Operating System.

 

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Cisco 6500 Series: Retired Veteran or Re-discovered Super Soldier?

December 27 2011 , Written by Cisco & Cisco Router, Network Switch Published on #Cisco Switches - Cisco Firewall

 

Why Cisco 6500 Series is here to stay?

Cisco-6500-switches.jpg

Tried and true isn't a descriptor awarded lightly. It's earned only after emerging battle-hardened from the front lines. It doesn't matter if you're the only survivor of the super-soldier program, or the flagship switch in the armada that is Cisco - history speaks for itself. For just a moment let's take a quick look at that history.

 

 

The Cisco 6500 was debuted in 1999 at the end of a decade that brought us legends such as Pogs, Street Fighter 2, and the Macarena. Even the popularity of the internet was only beginning to catch on.

 

 

 

 

 

We began with the Supervisor 1 and its 32gb switch fabric. Next, we graduated to the Supervisor 2 still at 32gb but with the ability to go to 256gb with the switch fabric module. Then we got the Supervisor 720. The 720 introduced 720gb switch fabrics, and then eventually the VSS (virtual switching system) which expanded even further to an upwards of 1.4Tbps!



Now, Cisco has debuted the Supervisor 2T which grows the upwards limits to 2Tbps, and doubles the per slot bandwidth from 40gb to 80gb! 

In addition to the newer supervisor engines, the chassis has also evolved. Now with the E series chassis, the Cisco Catalyst 6500 is capable of supporting the larger wattage power supplies and the newer supervisors and line cards. While it looks the same, these subtle differences help push the platform into the next generation.

 

 

What does that mean for the future of the Cisco 6500 platform?



Well with the announcement of new non-blocking 10gb cards and mention of 40gb support coming, it means that the Cisco 6500 series is here to stay. Some are saying it's here to stay for another 10 years. Bold words from an already aging platform. However, I'm reminded of the old adage "if it ain't broke, don't fix it." The Cisco 6500 switch was built around the idea of expandability, and dependability. It has proven itself time and again in both arenas.

 

So what does this mean for people who purchase pre-owned network hardware or are interested in the Catalyst 6500 switches? It means that purchasing a Cisco 6500 is an investment, and a wise one at that.

 

For people that already have the platform? They can continue to grow as needed, and as their companies and organizations grow. A recent Network World article mentioned that Cisco says it has 25,000 customers for the Catalyst 6500 and 700,000 chassis installed worldwide. That same article quoted John McCool, senior vice president and general management of Cisco's core technology group, saying: "We'd be silly to walk away from that installed base and loyal set of customers."

 

Knowing that Cisco is only continuing to develop for the 6500 platform is peace of mind that your budget dollars were spent well. In addition, new cards and expansions mean price drops and pre-owned market availability on current cards like the Supervisor 720s and 6700 series line cards in the not too distant future.

 

Cisco engineers like me are ready and willing to help you talk through your 6500 growth, and the needs and requirements that come along with it. We can help you navigate the sometimes slippery slope of your network hardware upgrades and save you time and money along the way.  We'd be happy to chat more in depth on the topic!

 

All things considered, the best just keeps getting better. The Cisco 6500 is here to stay and no one should feel bad about having this shield-slinging super-hero anywhere in their network. After all, it takes a veteran to show the new guys the ropes.

 

 

Comments from some Cisco fans:

 It still has its uses, but IMHO the highly oversubscribed, high latency networking architectures of the past won't make sense in the modern Data Center even at the access layer. Even looking at newer Cisco products like the 5548, let alone even higher density products from companies like Force10, Juniper, Brocade and Arista, which have substantially higher densities, substantially lower cost per port, substantially better performance across the board. Not to mention they all use a tiny fraction of the power and space and emit a tiny fraction of the heat. 

 

  Art Fewell: Cisco 6500 iEven re-purposing this box in the campus has limited utility because of the power, space and heating requirements. Given that the price of 10gig is coming down drastically (on other platforms) and most campus access switches come with 10gig uplinks, so many enterprises are upgrading their campus cores to support higher densities of 10gig. Other platforms can support 64 10gig ports in 1 rack unit with again a small fraction of the overhead costs. These newer platforms have such a lower cost basis that even used 6500's are substantially more expensive. Even keeping an existing 6500 is often much more in overhead costs than purchasing newer higher density equipment.       

 

Jason: Cisco 6500 is like the C-130 of the network devices. It does the heavy lifting of being the core router or switch of any enterprise or simply aggregating multiple devices on the edge of network. I think the reason it will go on for another decade, are the service modules, like ACE, NAM, VPN, FWSM, AIP etc... I think without these modules, having a 6500 in a SMB, would have been over kill.... The idea of integrating modules in 6500 is the main life saver of this legendary network ANVIL.                        

 Ali_A: I have been working with C6500 since 2000 .great product with great features. You can do whatever you want with the switch .it can be your Service Chassis switch, Campus, Core , … . I always love them and happy to hear that Cisco have plan to support them (maybe) for another decade. The C6500 show its stability and versatility it the battlefield.i still have C6500+SUP-2 with FWSM installed as datacenter service chassis with no problem and constant software update (SUP-2 lasted software update was 2010 even the device is EOS) take the product survived longer. Also the great blue-print, Deign guide , Cisco-SAFE for C6500 make everything straight when you want to deployment the switch in a scenario , more easier without the risk of wrong deployment or down-time.                    

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Cisco Static Routes FAQ: How to Use It?

December 23 2011 , Written by Cisco & Cisco Router, Network Switch Published on #Cisco Switches - Cisco Firewall

Static routes while manually intensive to keep up, are a very quick and effective way to route data from one subnet to different subnet. Let’s start with the basics.

What is a static route?Holiday-Tree-of-Knowledge.jpg
- a static route is a hard coded path in the router that specifies how the router will get to a certain subnet by using a certain path.

What do you mean by "hard coded"?
- you or someone has typed in the network ID and the next hop to get to the network specified

How do I add a static route into my Cisco router?
- Pretty simple
router# config t ; get into the configuration mode
router(config)# ip route A.B.C.D (destination network/host) A.B.C.D (mask) A.B.C.D (next hop); this is a simple static route

Are there any other ways to name the next hop except by using an IP address?
- Yes, you can use the port name i.e. ethernet0, E0, S0 and so on

What is "distance metric" that I can add at the end of the command?
- All routes have a value that allows the router to give a priority to which type of routing is used first. In static routes, the value is 1 which means no matter what other protocol you may have running like OSPF or RIP, the static route will always be used first. This can be changed to special needs. for example, if you have a frame link with ISDN back up, you can static routes for the frame and a second set of the same static routes but with a distance matric of 255. This means while the frame is up, it goes first but when the frame goes down, the router will try to use the 2nd static which is normally ignored due to the 255 value.

Why do I want to use static routes when there are neat routing protocols like OSPF?
- static routes are easy, no overhead either on the link or the the CPU of the router. They also offer good security when coupled with a tight IP mask like 252 which gives only 2 hosts on a given link

If static routes are so easy, why not use them all the time?
- Static routes while easy can be overwhelming in a large or complicated network. Each time there is a change, someone must manually make changes to reflect the change. If a link goes down, even if there is a second path, the router would ignore it and consider the link down.

One of the most common uses of a static map is the default classless route
- ip classless
- ip route 0.0.0.0 0.0.0.0 [next hop]

This static map says that everything is remote and should be forwarded to the next hop( or supernet) which will take care fo the routing.

Dial on demand is also a big user of static routes. Many times with dial up or ISDN, you do not have the bandwidth or you do not want to pay the connection fees for routing updates so you use static routes.

Static routes allow you to set up load balancing after a fashion. Keep in mind that the IOS load balances across routes first and not interfaces. The easiest way to configure multiple routes on the same interface is to use the secondary IP command

Router 1
!
interface serial 0
 ip address 192.0.0.1 255.255.255.0
 ip address 192.0.0.2 255.255.255.0 secondary ! second route on same interface
 
interface serial 1
 ip address 192.1.0.1 255.255.255.0
 ip address 192.1.0.2 255.255.255.0 secondary
 
ip route 200.2.0.0 255.255.255.0 196.0.0.4; goes to serial 0
ip route 200.2.0.0 255.255.255.0 196.0.0.5; goes to serial 0
ip route 200.2.0.0 255.255.255.0 196.1.0.4; goes to serial 1

Router 2
!
interface ethernet 0
 ip address 200.2.0.1 255.255.255.0
!
interface serial 0
 ip address 196.0.0.4 255.255.255.0
 ip address 196.0.0.5 255.255.255.0 secondary
!
interface serial 1
 ip address 196.1.0.4 255.255.255.0
 ip address 196.1.0.5 255.255.255.0 secondary
 
The traffic would go out router 1 across the two IPs on serial 0 first then across 1 IP on serial 1
This gives you unequal load balancing.
 
Notes: This is just the basics of static routing. You can get very creative if you want and take things further then described here. I would suggest "Routing TCP/IP Vol 1" from Cisco Press for more information.

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Network Switches: Functions & Types of Switches

December 22 2011 , Written by Cisco & Cisco Router, Network Switch Published on #Cisco Switches - Cisco Firewall

Functions of a Network Switch

A switch is a device that is used at the Access or OSI Layer 2; a switch can be used to connect multiple hosts (PCs) to the network.

 

Unlike a hub, a switch forwards a message to a specific host. When any host on the network or a switch sends a message to another host on the same network or same switch, the switch receives and decodes the frames to read the physical (MAC) address portion of the message.

 

Forwards Frames with MAC address

When a message is sent between hosts on a network or the same switch, the switch checks its MAC address table for the destination address. A switch MAC address table contains a list of all active ports, host or PCs MAC addresses that are attached to it. If the destination MAC address is not found in the table, the switch will not have the necessary information to forward the message. When the switch cannot determine where the destination host is located, it will flood or forward the message out to all attached hosts. Each host compares the destination MAC address in the message to its own MAC address, but only the host with the correct destination address processes the message and responds to the it.

 

How Switches Learn MAC addresses

A switch builds its MAC address table by examining the source MAC address of each frame that is sent between hosts. When a new host sends a message or responds to a flooded message, the switch immediately learns its MAC address and the port to which it is connected. The table is dynamically updated each time a new source MAC address is read by the switch. In this way, a switch quickly learns the MAC addresses of all attached hosts.

 

Collision Prevention

A switch prevents collisions by providing a circuit between the source and destination ports. This circuit provides a dedicated channel over which the hosts connected to the various ports on the switch can communicate. Each port is allocated with a separate bandwidth; these separate circuits allow many conversations to take place at the same time, without collisions occurring.

Switch to PC connection

 

 

Main Types of Switches

Fixed configuration switches:- 

These types of switches are fixed in their configuration. What that means is that you cannot add features or options to the switch beyond those that originally came with the switch. The particular model you purchase determines the features and options available. For example, if you purchase a 24-port gigabit fixed switch, you cannot add additional ports when you need them. There are typically different configuration choices that vary in how many and what types of ports are included.

 

Modular switches: -

These types of switches offer more flexibility in their configuration. Modular switches typically come with different sized chassis that allow for the installation of different numbers of modular line cards the line cards actually contain the ports. The line card fits into the switch chassis like expansion cards fit into a PC. The larger the chassis, the more modules it can support.

 

Stackable Switches/

Stackable switches can be interconnected using a special back cable that provides high-bandwidth between the switches. Cisco introduced StackWise technology in one of its switch product lines. Stack Wise allows you to interconnect up to nine switches using fully redundant back plane connections. As you can see in the figure, switches are stacked one atop of the other, and cables connect the switches in daisy chain fashion. The stacked switches effectively operate as a single larger switch. Stackable switches are desirable where fault tolerance and bandwidth availability are critical and a modular switch is too costly to implement. Using cross-connected connections, the network can recover quickly if a single switch fails. Stackable switches use a special port for interconnections and do not use line ports for inter-switch connections. The speeds are also typically faster than using line ports for connection switches.

 

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What Is a Layer 3 Switch? Router vs. Layer 3 Switches

December 12 2011 , Written by Cisco & Cisco Router, Network Switch Published on #Cisco Switches - Cisco Firewall

Layer 3 switches were conceived as a technology to improve on the performance of routers used in large local area networks (LANs) like corporate intranets. The key difference between Layer 3 switches and routers lies in the hardware technology used to build the unit. The hardware inside a Layer 3 switch merges that of traditional switches and routers, replacing some of a router's software logic with hardware to offer better performance in some situations.


Layer 3 switches often cost less than traditional routers. Designed for use within local networks, a Layer 3 switch will typically not possess the WAN ports and wide area network features a traditional router will always have.

 

Discussion: Router vs. Layer 3 Switches   ---from Cisco learning home

Q: As we all know that Layer 3 switch can perform the routing tasks if routing is enabled. But I`ve some questions regarding this:

 1. What is the main difference between this two?

 2. What is the choosing criteria between this two i.e. when should I use which one? What’s about the cost effects?

 3. Why router is needed if there is existence of Layer 3 Switch?

 

Re1: L3 switches do not have WAN interfaces.

You can connect Ethernet circuits to a switch so you only need a router if you want to connect traditional circuits such as E1 E1 SDH or old technology such as X21 V35 or async circuits. As far as I know Call Manager Express does not run on a switch but does on a router. Switches support Wi-Fi controller, Firewall so are quite powerful. So you need to understand the business requirement before deciding router or switch. Also routers can include switch modules.

 

Re2: If it routes, it's a router.  说明: https://learningnetwork.cisco.com/4.5.3/images/emoticons/happy.gif

L3-switch is a marketing term.  It's a router with only Ethernet interfaces and lots of them.  It also has a switching function to it. Which makes it both a router and a switch? The differences will vary based on model.  It depends...  Cost varies as well, everywhere from inexpensive to very expensive! And truly there isn't a "need". You need an L3 device of some sort to exit your subnet. How you design that, or what specific piece you use is entirely up to you.

 

Re3: Traditionally, Routers were devices that connected the LAN to the WAN and switches were just LAN devices and you may add a layer 3 switch to the lan if you had some vlans and didn't want to use a router.

 

However, as technology changes, the tradition of the WAN and LAN are fading.  My "WAN" links are actually 1 gig single mode fiber circuits that terminate to an ethernet fiber interface on a Layer 3 switch, a 6500, 4500, 3750 or even a 3560.  Now some will say that I have a MAN with those kinds of links.  It seems that as Scott said, Cisco Marketing is still stuck on calling a router a device that terminates a traditional WAN link,  I do agree that if the device routes, it is a router.... to some degree.

 

One thing I did notice regarding routers and layer 3 switches, and I will admit that router model and IOS version may play very heavily into this, and that is Routers seem to support more traffic monitoring features, such as netflow and nbar where as Layer 3 switches don't seem to have that kind of support.... until you get to the 6500.

 

Re4: Technically, the differences are:

1- L3 Switch do switching at layer 3 by preserving the source and destination mac and preserving the TTL value of the IP header of the 1st routed packet, so the first packet is routed using normal routing lookup, but after that all packet are switched.

2- router do normal routing lookup, but by introducing fast switching and CEF, packets are also now switched on a router.

3- Switches doesnt support some QoS features.

4- Switches doesnt support NAT.

5- The forwarding on switches is done on ASIC (Application Specific Integrated Circuits) which is done in hardware rather than a software.

6- Forwarding on routers are done in a software.

7- router supports different WAN technologies (modules) unlike switches.

 

Re5: I was just thinking about this.  I didn't learn about Layer 3 switches until the bcmsn.  I know in CCNA they were still really pushing the router vs switch concept.  Talk about throwing a monkey wrench into things when you throw in the concept of Layer 3 switch.

 

So to review:

1. A pure router will do just that, typically no switch ports, in today’s cisco world I don't even know if they make one of these, wouldn't that be something like an ASA with 1 or (2) 100 mb or gig ports with a serial port or similiar?

2.  A switch will just allow connections to edge devices, a true layer 2 switch like a 2960, Int vlan's is what allows management of the switch at layer 3.  No routing between vlans, this is where router on a stick comes into play.

3.  A layer 3 switch integrates both abilities, but it depends on the model on how integrated and featurific it is.  Will it support netflow?  Will it route between vlans?  If you do a show ip route what will be displayed?  How does it implement vlans, is it traditional vlan.dat file or will it do the switching way with show vlan? -- The simplest true layer 3 switch will support all switching features, but have the ability to do routed ports and route between the vlans.  I have had a Integrated services router like a 1760 or 3725 or similiar where they had a small switch module, say 4-24 (100).

 

The definition of a layer 3 switch also may include the ability for a port to be either a routed port or a switched port, the commands switch port vs no switch port followed by having to assign it an ip address.

 

This is another point that also took some getting used to.  In a port that can be either layer 2 or layer 3, or strictly layer 3 or layer 2.    Example, a router can only do layer 3, so to do inter vlan routing  while connecting to another switch via  trunk port you have to give it sub interfaces to a physical switch port, give each one its own ip address and tag it with the encapsulation dot1q #.  Router on a stick, vs. switchport mode trunk command with layer 3 interfaces via the "int vlan 1" with an ip address assignment.

 

While I understand the ccna approach to teaching fundamentals and where thing started, it no doubts confuses someone especially when a question asks about the differences between a hub/switch/router.  In today’s world, hubs don't really exist, and in a large company odds are you’re going to be using a layer 3 switch.

 

Re6: Not sure that is accurate. I think most layer 3 switches can handle BGP, but to what extent? Full tables? Probably not. Dishing out money for 2 Cisco 2821's or Cisco 2921's is going to be way cheaper than purchasing another Cisco 6500 for our network....not to mention our Catalyst 6500 already does a lot of work...and now I am going to throw BGP at it....AH it would just shut off and give me the middle line card!

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Cisco Club: Cisco Catalyst & Cisco Catalyst Switches

December 6 2011 , Written by Cisco & Cisco Router, Network Switch Published on #Cisco Switches - Cisco Firewall

Catalyst is the brand name for a variety of network switches sold by Cisco Systems. While commonly associated with Ethernet switches, a number of different interfaces have been available throughout the history of the brand. Cisco acquired several different companies and rebranded their products as different versions of the Catalyst product line. The original Catalyst 5000 and 6000 series were based on products originally developed by Crescendo Communications. The 1700, 1900, and 2800 -series Catalysts came from Grand Junction Networks, and the Catalyst 3000 came from Kalpana in 1994.

 

In addition, Cisco increasingly offers routers with switching capabilities, and indeed Cisco's 7600 router line and 6500 switch line have interchangeable parts. Even Cisco's smaller routers, including their newest "ISR" series, can have switch modules installed in them - basically making Cisco's smaller switches fully integrated devices.

 

Operating Systems

In most cases, the technology for the Catalyst Switch was developed separately from Cisco's router technology. The Catalyst switches originally ran software called CatOS rather than the more widely known Cisco IOS software used by routers. However, this has changed as the product lines have merged closer together. In some cases, particularly in the modular chassis switches, a configuration called 'Hybrid' has emerged - this is where the layer 2 functions are configured using CatOS, and the layer 3 elements are configured using IOS. 'Native IOS' can also be found with newer software versions that have eliminated CatOS entirely in favor of IOS, even on hardware that originally required CatOS.

 

The latest version of IOS for the Catalyst 6500 series is 12.2(33)SXI which enables In-Service Software Upgrade (ISSU) via IOS Software Modularity.

 

Some newer Catalyst switch models (with recent versions of the Cisco IOS) also allow configuration via web-based graphical interface module which is hosted on a HTTP server located on the switch. The IOS config-mode command 'ip http-server' will enable this style of configuration. In series 12.x IOS, 'ip http-server' is always on as a factory default. The Catalyst 3750-series of switches is an example of a Cisco Catalyst switch that allows this style of GUI configuration via HTTP.

 

Some newer models of Catalyst switches (called Catalyst Express) no longer allow access to IOS or CatOS at all - these switches can only be configured by using a Graphical User Interface (GUI).

 

CatOS

CatOS (Catalyst Operating System) is the discontinued operating system for many of the Catalyst brand of legacy network switches. It was originally called "XDI" by the switching company Crescendo Communications, Inc. Cisco renamed it to CatOS when they acquired Crescendo in late 1993.

 

CatOS ran on switches such as 1200, 4000, 4500, 5000, 5500, 6000, 6500 series. CatOS can still run on some of Cisco's modular switches, "hybrid" mode. In hybrid mode, the NMP (switch processor) runs CatOS and the route processor runs Cisco IOS.

 

Interfaces

As Catalyst devices are primarily Ethernet switches, all modern Catalyst models have Ethernet interfaces, ranging from 10 Mbit/s to 10 Gbit/s depending on the model. Some models can accommodate Asynchronous Transfer Mode interfaces which can be used to bridge Ethernet traffic across wide area networks. Other models can support T1, E1, and ISDN PRI interfaces to provide connections to the PSTN. Legacy models supported a variety of interfaces, such as token ring, FDDI, and 100BaseVG, but are no longer sold by Cisco Systems.

 

Most models have basic layer 2 functions and are capable of switching Ethernet frames between ports. Commonly found additional features are VLANs, trunking (Cisco proprietary ISL or IEEE 802.1Q) and QoS or CoS. The switches, whether IOS or CatOS, are fully manageable.

 

Many Catalysts that run IOS are also capable of functioning as a router, making them layer 3 devices; when coupled with TCP and UDP filtering, these switches are capable of layer 2-4 operation. Depending on the exact software image, a Catalyst that runs IOS may be able to tackle large-scale enterprise routing tasks, using router technologies like OSPF or BGP.

 

Most chassis-based Catalyst models have the concept of field-replaceable "supervisor" cards. These work by separating the line cards, chassis, and processing engine (mirroring most Cisco router designs). The chassis provides power and a high-speed backplane, the line cards provide interfaces to the network, and the processing engine moves packets, participates in routing protocols, etc. This gives several advantages:

  • If a failure occurs, only the failed component needs to be replaced (typically a line card or supervisor). This means faster turnaround than having to uncable, unbolt, pull out, replace, re-bolt, and re-cable an entire switch, which may be as large as a quarter-rack, weigh over 150 pounds, and service over 500 cables.
  • A redundant supervisor engine may be installed to rapidly recover from supervisor failures. This is subject to restrictions (as some switches don't support redundant supervisors), but typically results in restoration times under 90 seconds.
  • A supervisor engine may be upgraded after purchase, increasing performance and adding features without losing any investment in the rest of the switch.

 

Additionally, most high-end switches off-load processing away from the supervisors, allowing line cards to switch traffic directly between ports on the same card without using any processing power or even touching the backplane. Naturally, this can't be done for all traffic, but basic layer-2 switching can usually be handled exclusively by the line card, and in many cases also more complex operations can be handled as well.

 

Management

Cisco switches are very popular for a number of reasons, including advanced customization and manageability. The switches can be configured using a serial console or a telnet session (or ssh if the correct OS is loaded along with the ssh keys generated). SNMP allows monitoring of many states, and measurement of traffic flows. Many devices can also run an HTTP server, but this is often disabled because of the security problems it creates - either because it's not encrypted, or because of the relatively frequent security vulnerabilities in the Cisco http daemon itself. Some Cisco switches focused on smaller organizations forego a command line interface and offer ONLY a web/html interface for configuration and management.

 

Configuration of the switch is done in plain text and is thus easy to audit - no special tools are required to generate a useful configuration. For sites with more than a few devices it is useful to set up a TFTP server for storing the configuration files and any IOS images for updating. Complex configurations are best created using a text editor (using a site standard template), putting the file on the TFTP server and copying it to the Cisco device. However, it can be noted that a TFTP server can present security problems.

 

Stackwise

Cisco StackWise is a technology offered by Cisco Systems that allows for up to nine Catalyst switch---3750 series switches to operate as though they were one 32-Gbit/s switch. This allows for greater resiliency, and performance.

 

One switch from the stack will act as the master switch. The master switch will maintain the stack and allow you to configure and monitor the whole stack as though one via a single console.

 

If one switch fails the remaining switches will continue to operate by looping back any information that would normally traverse the failed switch, effectively bypassing it. If the master switch fails, the next switch in the stack will automatically take over as master. This feature means greater redundancy, as one switch's failure will not bring about a failure of the entire stack.

As each switch contains the entire configuration for the stack one of the benefits of this technology is the ability to replace a down switch (any including master) with a new un-programmed switch. The stack will configure the new switch on the fly and allow for minimal downtime

 

StackWise effectively replaced the GigaStack found on lower-price models such as Catalyst 35xx and 29xx series.

 

Recently, there is a new variation of the technology, known as Cisco Stackwise Plus, offering 64Gbit/s nonblocking switching fabric speed.

 

Master Selection

The master switch of a stack is determined in the following order.

  1. User specified.
  2. The switch with the most advanced IOS, i.e. Advanced IP Services IPv6 (AIPv6), then Enhanced Multilayer Software Image (EMI) and then Standard Multilayer Software Image (SMI).
  3. Programmed switch. A configured switch will preside over a switch with just the defaults.
  4. Uptime. The switch that has been running the longest.
  5. MAC address. The switch with the lowest MAC address.

 

Models/Types of Cisco Catalyst Switches

Like most Cisco product lines, the Catalyst Switch series evolves fairly rapidly. There are two general types of Catalyst switches: fixed configuration models/ fixed-configuration switch that are usually one or two rack units in size, with 12 to 80 ports; and modular switches/ chassis-based switch in which virtually every component, from the CPU card to power supplies to switch cards, are individually installed in a chassis.

  • As of 2011, the most popular fixed configuration switches are the WS-C2960, the WS-C3560 and WS-C3750 series at the high end, an entry level managed "express" series - with models beginning WS-CE (configurable by web interface only, no command line interface), the "ME" metroline series of switches, and a new "Small Business" series coming from Cisco's acquisition of Linksys. In addition, there are many excellent legacy switches suitable for most business and service provider needs no longer offered directly through Cisco (WS-C2950, WS-C3550 for example). Cisco fixed configuration switches come with a bewildering assortment of features (10/100 ports versus 10/100/1000 ports, some with power over Ethernet, some with varying types of gigabit and 10gig uplink ports, some with standard or enhanced software, varying power supplies) and it is difficult to tell what features a switch has (aside from the number of ports) from a visual inspection, and similar-appearing switches can have dramatically different features.

 

Cisco Model Names & Switch Features

In general, switch names start with WS-C, followed by the model line (2960). A letter at the end of this number signifies a special feature, followed by the number of ports (usually 24 or 48) and additional nomenclature indicating other features.

 

Cisco modular switches are much larger and are entirely configurable, beginning with a chassis, power supplies, the choice of supervisory engines (CPU mainboards), and switch modules. Among Cisco's modular series are:

  • The Cisco Catalyst 6500 Series is a chassis-based switch family. This series can support interfaces up to 10 Gigabit Ethernet in speed and redundant Supervisor modules.
  • The Cisco Catalyst 5500 Series and Cisco Catalyst 5000 Series is a chassis-based switch family. The Cisco Catalyst 5000 Series is acquired from another company. This entire series has now reached end-of-sale.
  • The Cisco Catalyst 4900 series is a fixed-configuration switch. Uplink interfaces are either SFP ports or 10 gigabit Ethernet, with 48 copper ports of 10/100/1000 Ethernet.
  • The Cisco Catalyst 4500 Series is a mid-range modular chassis based Switch manufactured by Cisco System.
  • The Cisco Catalyst 3000 and 3100 series switches are switches for use in blade-enclosures: the Catalyst 3032 is a Layer2 switch and the Catalyst 3130x and 3130G are blade-switches for the Dell M1000e enclosure.
  • The 1000 switch family is considered an edge device, having many functionalities that can be built as the device is very modular.

Cisco-Catalyst.jpg

To sum up, the Cisco Catalyst range is designed to meet the needs of a wide range of customers—from small to medium businesses, right up to large enterprise networks and service providers. Cisco Catalyst switches provide high performance, scalability, manageability, and many other intelligent features that ensure their success to date.

 

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Firewall, Overview and Features You Should Know

November 29 2011 , Written by Cisco & Cisco Router, Network Switch Published on #Cisco Switches - Cisco Firewall

Generally, a Firewall protects your computer from intrusion (scanning or attack) by hackers or script kiddies while it is connected to the Internet. A firewall examines electronic data coming in to, or out of, a computer (or network - computers joined together by wires or wireless connection) and compares it to rules it has been given. If that data matches the rules which say it is OK, it will let the data pass. If it doesn't, it blocks the data. To be simple, just think of a Firewall as a piece of software (or hardware for those with more computers) that keeps the bad guys out and let the good ones in. It stops hackers and script kiddies from gaining access to your computer and the information on it.

Hardware-firewall.jpg

 

There are many people who still use the internet without thinking twice about protecting themselves when online. Most of these people are home or small business users who never give it a second thought, or just don't understand enough about the risks to worry. Using the internet without a firewall can be explained quite easily - You wouldn't leave your house or office unlocked, or with the windows and doors wide open so that anyone can walk in and look around, or even steal your items, but using the internet isn't much different than that. If you are online without a firewall you are leaving it wide open to attack, and intruders and thieves could view or steal your information.

 

So for people who use the internet, no matter it is a home, or an enterprise, a firewall is an essential hardware or software to help to protect your privacy and data on your computer by stopping hackers from gaining control of your system.

 

A firewall also prevents confidential information on your system from being sent without your permission. This could be your passwords, bank details and other personal information.

 

About Personal Firewall & Hardware Firewall

A Personal Firewall (also known as a desktop firewall, or Software firewall) is installed on each computer that is connected to the internet and monitors (and blocks, where necessary) internet traffic. It is used to help protect a single Internet-connected computer from intruders. Personal firewall protection is useful for users with "always-on" connections such as DSL, cable modem or dial-up connections.

 

Hardware firewall's can be purchased as a stand-alone product but more recently hardware firewall's are typically found in broadband routers, and should be considered an important part of your system and network set-up, especially for anyone on a broadband connection. Hardware firewalls can be effective with little or no configuration, and they can protect every machine on a local network. Most hardware firewalls will have a minimum of four network ports to connect other computers, but for larger networks, business networking firewall solutions are available.

 

Software and Hardware Firewall

The differences between a software and hardware firewall are vast, and the best protection for your computer and network is to use both, as each offers different but much-needed security features and benefits. Updating your firewall and your operating system is essential to maintaining optimal protection, as is testing your firewall to ensure it is connected and working correctly.

 

Notes

Intro of Most Popular CISCO Firewall Hardware: About Cisco ASA 5500 Series

Designed as a core component of the Cisco Self-Defending Network, the Cisco ASA 5500 Series provides proactive threat defense that stops attacks before they spread through the network, controls network activity and application traffic, and delivers flexibleVPN connectivity. The result is a powerful multifunction network security appliance family that provides the security breadth and depth for protecting home office, branch office, small and medium-sized business, and enterprise networks while reducing the overall deployment and operations costs and complexities associated with providing this new level of security.

 

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