Solved

shutdown before bgp configuration

Posted on 2012-03-26
7
399 Views
Last Modified: 2012-04-10
I have an existing BGP connection ISP1 and I am in the process to add another BGP connection with ISP2. It will be a multihomed failover with single router. My question is do I have to shut down my interfaces to ISP1 and ISP2 before configuring the multihomed failover? Thx
0
Comment
Question by:biggynet
  • 3
  • 3
7 Comments
 
LVL 17

Expert Comment

by:Garry-G
ID: 37766031
One question comes to mind - why failover, why not dual homed with load balancing over both ISPs? If it's a price or performance issue, you could always just do some incoming or outgoing prepends on the more expensive (or less performant) link ...
As for the shutdown, I would not see a reason to shut the existing connection down. Though, do make sure you know what you're doing and have suffcient filters in place to avoid announcing routes learned from one ISP to the other and vice versa (though I suppose any decent ISP should have filters in place on their end, apart from a max prefix setting). Once your second session is up, make sure the anouncements sent look correct ("show ip bgp nei x.x.x. advertised" on Cisco)
0
 

Author Comment

by:biggynet
ID: 37766116
"why failover" because that is my customer's choice. So if I understand correctly, there is not need to shut down the interfaces. Correct?
0
 
LVL 15

Accepted Solution

by:
Robert Sutton Jr earned 250 total points
ID: 37766141
What type of device are you using and what IOS/Firmware version are you using? Does it support "soft reset"?
Either way fwiw:
If you subsequently change a BGP filter, weight, distance, version, or timer, or make a similar configuration change, you MUST reset BGP connections for the configuration change to take effect.

Hope this helps.
0
Portable, direct connect server access

The ATEN CV211 connects a laptop directly to any server allowing you instant access to perform data maintenance and local operations, for quick troubleshooting, updating, service and repair.

 

Author Comment

by:biggynet
ID: 37766186
Cisco 3825
0
 
LVL 17

Assisted Solution

by:Garry-G
Garry-G earned 250 total points
ID: 37766860
No, shutdown is not necessary - otherwise, how would you expect ISPs to work when they have dozens or hundreds of BGP sessions on a router and need to add one?
Will you be receiving just a default route from both ISPs or a full table? I guess the 3825 would be pretty hard pushed receiving two full feeds (though it can handle it)... do not attempt with anything less than 768 megs of memory ;)

How do you plan to run the failover? Prepends, MED, ... ?
0
 

Author Comment

by:biggynet
ID: 37767029
Failover = prepend.
Please tell me more about full routing table and default route from the ISP perspective. Let say I want a full table from the ISP, how would they advetise that? With many many NETWORK commands? Thx
0
 
LVL 17

Expert Comment

by:Garry-G
ID: 37767191
No ... prefixes learned through BGP are usually automatically advertised to downstream BGPs ...

If your customer only wants backup, not load balancing/optimization, you might as well let both ISPs just advertise a default route, less strain on the router, and you won't lose much functionality either ... OTOH, taking full prefixes, albeit with prepends on the less desired link, will allow you to reach destinations that for some reasons are not available through the primary link ...
0

Featured Post

Portable, direct connect server access

The ATEN CV211 connects a laptop directly to any server allowing you instant access to perform data maintenance and local operations, for quick troubleshooting, updating, service and repair.

Question has a verified solution.

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

Suggested Solutions

Meet the world's only “Transparent Cloud™” from Superb Internet Corporation. Now, you can experience firsthand a cloud platform that consistently outperforms Amazon Web Services (AWS), IBM’s Softlayer, and Microsoft’s Azure when it comes to CPU and …
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…
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…
This video gives you a great overview about bandwidth monitoring with SNMP and WMI with our network monitoring solution PRTG Network Monitor (https://www.paessler.com/prtg). If you're looking for how to monitor bandwidth using netflow or packet s…

808 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