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Posts tagged Lab
Troubleshooting Lab #1
Mar 5th
This will be the first in a series of troubleshooting labs. I will post a topology and the issue I’m seeing. Hopefully you guys will attempt to solve it and post your ideas, questions and solutions in the comments.
We’ll start with a relatively easy one. Today we are having an issue with BGP neighbor relationships not forming.
Here’s our Topology:
Here’s R1’s config:
hostname R1 ! ip cef ! interface Loopback0 ip address 1.1.1.1 255.255.255.255 ! interface Serial0/0 description To R2 ip address 10.1.1.2 255.255.255.254 ! router bgp 5000 no synchronization bgp log-neighbor-changes neighbor 2.2.2.2 remote-as 6000 neighbor 2.2.2.2 ebgp-multihop 2 neighbor 2.2.2.2 update-source Loopback0 no auto-summary ! ip route 0.0.0.0 0.0.0.0 10.1.1.3 |
And R2:
hostname R2 ! ip cef ! interface Loopback0 ip address 2.2.2.2 255.255.255.255 ! interface Serial0/0 description To R1 ip address 10.1.1.3 255.255.255.254 ! router bgp 6000 no synchronization bgp log-neighbor-changes neighbor 1.1.1.1 remote-as 5000 neighbor 1.1.1.1 ebgp-multihop 2 neighbor 1.1.1.1 update-source Loopback0 no auto-summary ! ip route 0.0.0.0 0.0.0.0 10.1.1.2 |
Now some show commands:
R2#sh ip bgp summ BGP router identifier 2.2.2.2, local AS number 6000 BGP table version is 1, main routing table version 1 Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd 1.1.1.1 4 5000 0 0 0 0 0 never Active R1#sh ip bgp summ BGP router identifier 1.1.1.1, local AS number 5000 BGP table version is 1, main routing table version 1 Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd 2.2.2.2 4 6000 0 0 0 0 0 never Active |
We see that the relationship will not form. You guys tell me why.
I’m attaching the .net file, with it and the configs above you should be able to replicate this easily.
The Troubleshooting Lab #1 .net file
(Don’t forget to change your paths)
BGP Communities
Feb 4th
Today’s post is about BGP Communities. Here is an explanation of them from Cisco:
“A community is a group of prefixes that share some common property and can be configured with the BGP community attribute. The BGP Community attribute is an optional transitive attribute of variable length. The attribute consists of a set of four octet values that specify a community. The community attribute values are encoded with an Autonomous System (AS) number in the first two octets, with the remaining two octets defined by the AS. A prefix can have more than one community attribute. A BGP speaker that sees multiple community attributes in a prefix can act based on one, some or all the attributes. A router has the option to add or modify a community attribute before the router passes the attribute on to other peers.”
Here is a table listing the Well Known Communities from Cisco:
CCIP Practice Lab #2
Feb 2nd
This is the second practice lab for my CCIP BGP and MPLS preparation. I’ve added my configs to the first post, let me know if I’ve missed anything. This lab has a lot of overlap with the last one, but I’ve added some more BGP-specific stuff in preparation for my upcoming exam. I have italicized all the changes. Here’s the topology:
(click image for fullsize)
Requirements
Core
- P1, P2, P3 and P4 run only MPLS and OSPF, no BGP.
- PE1, PE2, PE3 and PE4 will support EIGRP, OSPF and L2 VPNs to customers C1, C2 and C3.
BGP
- PE1 and PE4 will have an iBGP relationship and will be route reflectors for PE2 and PE3. Use the fewest commands possible.
- Configure MD5 authentication between CE4 and PE1 using the password “cisco1”.
- Configure MD5 authentication between CE4 and Peer1 using the password “cisco1”.
CCIP Practice Lab #1
Jan 28th
This is the first practice lab for my CCIP BGP and MPLS preparation. I have modified the existing topology to add another customer. This lab is somewhat basic, but it incorporates many different technologies.
(click image for fullsize)
Requirements
Core
- P1, P2, P3 and P4 run only MPLS and OSPF, no BGP.
- PE1, PE2, PE3 and PE4 will support EIGRP, OSPF and L2 VPNs to customers C1, C2 and C3.
BGP
- All PE routers will have iBGP relationships with each other. Use the fewest commands possible to accomplish this. Ensure multiple paths can be taken to peer with each router.
- PE1 and PE2 will have eBGP relationships with Peer1 and Peer2.
- Peer1 and Peer2 will inject networks from several loopbacks into BGP to simulate the internet.
- Peer1 and Peer2 will have an eBGP relationship.
MPLS and BGP Lab, Part 6
Dec 31st
This is the sixth post in the series, the goal of the series is to provide a guide for the MPLS and BGP Lab I posted awhile back. The labs consists of MPLS VPNs and BGP along with some OSPF, NAT, IPSEC and GRE exposure. I will be posting the files needed for this lab at the bottom. Here’s the topology and the requirements:
(click image for fullsize)
Requirements:
Internet
* The two Internet routers should serve as transit ASes. No other routers should permit transit traffic.
* Internet sites (modeled by loopbacks) should be accessible by all lan IPs.
