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
Solved

Loopback addresses and BGP

Posted on 2009-05-08
3
889 Views
Last Modified: 2012-05-06
I need a clarification to make is it correct to say that use of loopback interfaces as BGP source address is recommended since the loopback interface  unlike a physical Interface / subinterface does not go down . As such this reduces the flapping on the BGP tables in the network
0
Comment
Question by:sgknoc
3 Comments
 
LVL 43

Expert Comment

by:JFrederick29
ID: 24335961
Yes, assuming the router has multiple physical interfaces or paths to which the loopback can be reached.  If the router only has one physical interface or one path to it's neighbor(s), using a loopback doesn't provide any further stability.
0
 
LVL 10

Expert Comment

by:lanboyo
ID: 24335981
Well, certainly true on iBGP connections. eBGP requires connectivity to your peer, and usually this is on a single interface anyway.
0
 
LVL 1

Accepted Solution

by:
donnlee earned 500 total points
ID: 24342918
The following are best practices for BGP and addressing:
Case1: When configuring an iBGP session, use/configure the other router's loopback address.
Case2: When configuring an eBGP session, and there is only one link to the other router, use the other router's physical interface address (usually the address on the other side of the /30 or /31 link).
Case3: When configuring an eBGP session, and there are multiple links to the other router, use eBGP multihop and the other router's loopback address.

Because a router can have both iBGP and eBGP sessions, the above rules use the "other router" terminology.

All routers should be configured with a loopback address because IGPs (OSPF, IS-IS) will use that address for the router-id, and you almost always run BGP with an IGP.

I have been doing BGP for 14 years at Cisco and later at large Internet companies.
0

Featured Post

Networking for the Cloud Era

Join Microsoft and Riverbed for a discussion and demonstration of enhancements to SteelConnect:
-One-click orchestration and cloud connectivity in Azure environments
-Tight integration of SD-WAN and WAN optimization capabilities
-Scalability and resiliency equal to a data center

Question has a verified solution.

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

In the hope of saving someone else's sanity... About a year ago we bought a Cisco 1921 router with two ADSL/VDSL EHWIC cards to load balance local network traffic over the two broadband lines we have, but we couldn't get the routing to work consi…
Tired of waiting for your show or movie to load?  Are buffering issues a constant problem with your internet connection?  Check this article out to see if these simple adjustments are the solution for you.
After creating this article (http://www.experts-exchange.com/articles/23699/Setup-Mikrotik-routers-with-OSPF.html), I decided to make a video (no audio) to show you how to configure the routers and run some trace routes and pings between the 7 sites…
After creating this article (http://www.experts-exchange.com/articles/23699/Setup-Mikrotik-routers-with-OSPF.html), I decided to make a video (no audio) to show you how to configure the routers and run some trace routes and pings between the 7 sites…

829 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