Solved

Any one can answer the BGP Synchronization question ?

Posted on 2012-12-29
4
394 Views
Last Modified: 2012-12-31
Any one can answer the BGP Synchronization question ?

The topology is very simple. Router2---Router1--interface e1/1(ip address 111.1.1.1/24)

R1
router bgp 12
network 111.1.1.0 mask 255.255.255.0
 neighbor 2.2.2.2 remote-as 12
 neighbor 2.2.2.2 update-source Loopback0
router ospf 1
network 0.0.0.0 255.255.255.255 area 0

R2
router bgp 12
 synchronization
neighbor 1.1.1.1 remote-as 12
neighbor 1.1.1.1 update-source Loopback0
router ospf 1
network 0.0.0.0 255.255.255.255 area 0

R2#show ip bgp
   Network          Next Hop            Metric LocPrf Weight Path
* i111.1.1.0/24     1.1.1.1                  0    100      0 i

After R2 enabled synchronization, the network 111.1.1.0/24 in bgp table lost marker “>” in the bgp table.

Question:
In the case, synchronization rule means network 111.1.1.0/24 is inactive (meaning losing marker “>” ) in R2’ BGP table until this network goes into R2 via IGP. Now the network 111.1.1.0/24 already has gone into R2 via IGP. Why does the network 111.1.1.0/24 is still inactive in R2 BGP table after enabling synchronization in R2 ?
0
Comment
Question by:davidy2001
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 2
4 Comments
 
LVL 3

Expert Comment

by:Teeshirt
ID: 38730694
Your topology isn't desirable to enable synchronization.

You can disable synchronization if one of the following conditions is true:

- Your AS does not pass traffic from one AS to another AS.
- All the transit routers in your AS run BGP.
0
 

Author Comment

by:davidy2001
ID: 38730966
Thanks. No matter whether I connect other additional iBGP or EBGP router to Router2, or not, the effect should be the same. The network 111.1.1.0/24 must be active ( with marker ">") , and then it can travel to next EBGP. what i am concerned is why the network 111.1.1.0/24 is not active after enabling synchronization
0
 
LVL 7

Accepted Solution

by:
Phyo HTET AUNG earned 500 total points
ID: 38732162
You are speaking ibgp and ospf between R1 and R2.
What is result of "R2#show ip bgp x.x.x.x". It's "not synchronized"?


I got troubleshooting guide from iphelp



Refer Cisco Case Studies

Hope this help.
Regards
0
 

Author Comment

by:davidy2001
ID: 38733598
Great, thanks, phyohtetaung
If eBGP connect with R2, there two ways to let 111.1.1.0/24 reach the eBGP: 1, turn off synchronization at R2, 2, redistribute the route or publish it by igp though the route is marked with "r" in bgp table.
0

Featured Post

Create the perfect environment for any meeting

You might have a modern environment with all sorts of high-tech equipment, but what makes it worthwhile is how you seamlessly bring together the presentation with audio, video and lighting. The ATEN Control System provides integrated control and system automation.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

If you're not part of the solution, you're part of the problem.   Tips on how to secure IoT devices, even the dumbest ones, so they can't be used as part of a DDoS botnet.  Use PRTG Network Monitor as one of the building blocks, to detect unusual…
This article is a collection of issues that people face from time to time and possible solutions to those issues. I hope you enjoy reading it.
Viewers will learn how to connect to a wireless network using the network security key. They will also learn how to access the IP address and DNS server for connections that must be done manually. After setting up a router, find the network security…
Monitoring a network: why having a policy is the best policy? Michael Kulchisky, MCSE, MCSA, MCP, VTSP, VSP, CCSP outlines the enormous benefits of having a policy-based approach when monitoring medium and large networks. Software utilized in this v…

617 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question