What is VRF?

Question:

please explain me C2921-VSEC what is VRF also I have found that vrf can be configured on both router and switch. I have 3750 and 3800 so where should I configure vrf.

Answer:

VRFs in general used to virtualizes the routing tables where you can have multiple routing tables in one physical router
VRFs can be used with MP-BGP and MPLS for network like ISPs
also VRFs can be used locally to perform separation between multiple routing instances aka VRF lite
both can be used for Path isolation

useful links
http://packetlife.net/blog/2010/mar/29/inter-vrf-routing-vrf-lite/
http://www.cisco.com/en/US/docs/solutions/Enterprise/Network_Virtualization/PathIsol.html  C2951-VSEC

Original comes from http://switch.2329893.n4.nabble.com/3900-router-td14.html

Help with basic config of 819 using CP Express please

Question:

I set up a basic WS-C3560V2-24TS-S Linksys E2500 with the following information and connected to the

internet straight away without a problem:
I have spent several hours simply trying to get this basic information into the Cisco

819 using CP Express without success, i.e. I get no internet.  Rather than show my

inputs, I'd appreciate some guidance of the correct setup.  I am a novice so I'd

rather solve this issue using CP Express just to get connected in the first instance.

By the way, I have a static IP address, I connected the ethernet cable carrying the

internet to the internet port of the E2500 and an ethernet cable from one of the

ethernet ports of the E2500 to my PC.  For the 819, I connected the internet cable to

the GE WAN 0 port and the PC to one of the FE ports.  Thanks.

Answer:

just mark the thread as resolved and rate any post you found valuable.

PM me and we'll find a way to test it and see what is not working. WS-C3560X-48T-S  Original comes from http://www.kerchoonz.com/lilirouter

iBGP or IGP in this design?

Question:

According to this example Cisco 3925E from official CCNP book, the BGP design calls for making the packets flow over the route as shown.
And according to that book, two actions must take place for this design to work:

Make BGP specify a prefix as being best reached through a particular link (BGP PA settings). I'm fine with that, no questions here.
Need to run BGP between multiple routers. E1 and E2 must communicate BGP routes using iBGP connection and because packet forwarding between E1 and E2 goes through other routers (such as Core1 and Core2), those routers also need to run BGP.
Here is my question:

Instead of running iBGP on non-enterprise routers, can't we just add IGP to Enterprise routers and have them to redistribute their eBGP learned routes into IGP, forward them to enterprise network and leave the non-enterprise routers running IGP?

Answer:

i totally agree with you. An IGP (OSPF,EIGRP or IS-IS) would be even more flexible in this scenario that otherwise in the near future can represent some scalability problems should you add some routers more due to the fact that no BGP route reflectors are in place. If the Joseph guessing is right (you have a lot of prefixes) just use summarization and you will definitely see benefits in your design. Except for SP environment, iBGP should never be extensively deployed in an enterprise. You you want a more valuable opinion about this topic, Jeff Doyle (TCP/IP Vol 2) makes clear why we use BGP and ...it is very interesting Cisco3925E  For more info, please refer to http://lilirouter.soulcast.com/

Understanding show policy-map interface xx

Question:

I need to understand the WS-C3750X-24P-S difference between "total drop" and "no-buffer drop" in the output:

Router#sh policy-map int gi 0/0
GigabitEthernet0/0


  Service-policy output: SHAPE-OUT


    Class-map: class-default (match-any)
      441790059 packets, 219164243756 bytes
      30 second offered rate 23718000 bps, drop rate 228000 bps
      Match: any
      Queueing
      queue limit 64 packets
     (queue depth/total drops/no-buffer drops) 0/3447160/0
      (pkts output/bytes output) 443857262/223879827364
      shape (average) cir 40000000, bc 160000, be 160000
      target shape rate 40000000

Answer:

You can have drops due to rasons below

1. WRED dropping the packet
2. You excceded the configured rate and you are buffering the packet and you have exceeded the configured queue limit.
3. You are exceeding the confgured rate, you are trying to buffer the packet. But you have not reached the configured queue limit, but there is no buffer available to allocate the configured queue-limit

Drops due to 3rd Reason will come as " no-buffer drops"
Drops due to all the above reasons, WS-C3750V2-24PS-S Price is Total drops

For futher information, please refer to  http://www.journalspace.com/index.php?do=/blog/3405/influencing-eigrp-path-over-tunnel-interfaces/

Simple network architecture for redundant switches and firewalls?

Question:

We'll be building Cisco 3945 price a small remote site that will use two Windows 2008 servers.  We would like redundancy in firewalls, IPS's and switches.   Is it better to buy stand-alone ASA 5510s (with embedded IPS's) and 2960s, or is it a better option to buy a  Cat 6000 with FW modules.  We'll have several internet IP addresses available.  I don't know much about Nexus or latest HW options, so perhaps there's options I don't know about.  Thanks

Answer:

The Cat6500 with ASA-SM is far more expensive then standallone devices. If you think about the 5510 and the throughput is enough, then I would use the following equipment:

2* ASA 5515-X-IPS as Active/Standby

2* Cat 3750-X as a stack with redundant power-supplies.

That will give you a maximum of redundancy for an affordable price.

-- 

Don't stop after you've improved your network! Improve the world by lending money to the working poor:

http://www.kiva.org/invitedby/karsteni

For futher information, please refer to  http://www.3anetwork.com/cisco-cisco3945-sec/k9-price_p289.html

Enabling CEF Question

Question:

Hey, would WS-C3750X-48T-L  it be a wise move, to enable CEF on the WAN interface going to the Internet, if cef memory is currently at 98%.

AS of right now, this interface is process switching. The other two interfaces are cef switching.   

Answer:

I agree with Rick.

Your router will work better with CEF enabled on all interfaces.

About memory usage by CEF: your device is a SW based router that already has built a CEF table to be used for CEF switching. The table is populated by routing information ( topology driven) so adding the third interface to CEF should not cause a big increase in memory usage as the CEF table is already built and you should be able to see lower CPU usage with all interfaces running CEF.

Original comes from http://www.3anetwork.com/cisco-ws-c3750x-48t-s-price_p104.html

OSPF Database & routing table

Question:

Why would there be WS-C3560X-24T-L discrepancies between the ospf database and the entries in the routing table. If I do show ip ospf database there are a significant number of entries that are not shown but are in the network list under router ospf....

Why would this be? We are having occasional connectivity problems with 2 of the subnets that are not in the ospf database but are in the network router list.

Any help you can give is appreciated.

Alex

Sent from Cisco Technical Support iPad App

Answer:

As I said earlier, all routers with in an area would have the same topology database. That means, same entries.

The only thing i think u are missing is, you have to check it under the Router LSA for the advertising router.

show ip ospf database router <192.168.162.1>

Check the same command on the router in which u suspect its not there. WS-C3560X-24T-S Price