We value your feedback.
Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!
Solved
Any one can answer the BGP Synchronization question ?
Posted on 2012-12-29
Any one can answer the BGP Synchronization question ?
The topology is very simple. Router2---Router1--interfa
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 ?
The topology is very simple. Router2---Router1--interfa
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 ?
[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
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.
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.
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
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
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
Featured Post
Question has a verified solution.
If you are experiencing a similar issue, please ask a related question
How to set-up an On Demand, IPSec, Site to SIte, VPN from a Draytek Vigor Router to a Cyberoam UTM Appliance.
A concise guide to the settings required on both devices
This month, Experts Exchange’s free Course of the Month is focused on CompTIA IT Fundamentals.
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…
Michael from AdRem Software explains how to view the most utilized and worst performing nodes in your network, by accessing the Top Charts view in NetCrunch network monitor (https://www.adremsoft.com/). Top Charts is a view in which you can set seve…
Suggested Courses
Course of the Month8 days, left to enroll
715 members asked questions and received personalized solutions in the past 7 days.
Join the community of 500,000 technology professionals and ask your questions.