two ISP's over BGP

We have two Edge routers that we peer to for MPLS and Internet routes.
Both will be BGP.

Currently the ISP for the internet providers are just sending us a default routes that we just weight one over the other and i want to be cooler because the edge routers are 3845's.

Inbound traffic on both providers is pretty balanced for inbound.

Now obviously getting the isp's to send me a full BGP table is a bad idea but when i brought up the option of partial routes it seemed to be a grey area.

What are some of the medium to large business doing or any suggestions on how to improve our current system.

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Comments

networker050184

You can go with a partial and a default from each if you want. Might not see much of a performance increase depending on your traffic habits though. You will be getting the ISPs routes and a default so if you are using resources that are on that ISPs network you can go directly to them rather than routing through the other. If most of your traffic is destined to neither of the ISPs routes, then its not going to matter as you will still just use the default.

Just a warning, changing things in a production environment just to "be cool" isn't always the best idea from my experience. Reminds me of the time I decided that it would be cool to use VACL's before I had a complete understanding of them but I found them on Cisco's site. I ended up completely locking down a couple switches in the middle of the day.

Since that day I've never done anything on a live network that was cool. Two of my favorite sayings since that day - "Keep It Simple Stupid" and "if it ain't broke don't fix it." Well, one more - "The 7 Ps - Prior Proper Planning Prevents Piss Poor Performance." In other words, always have proper planning, completely understand what you are doing and sometimes the simplest solution is best.

Cyanic

networker050184 wrote: »

Just a warning, changing things in a production environment just to "be cool" isn't always the best idea from my experience. Reminds me of the time I decided that it would be cool to use VACL's before I had a complete understanding of them but I found them on Cisco's site. I ended up completely locking down a couple switches in the middle of the day.

Any production network should have configuration/change management in place so these "oops" are avoided. Here is a simple CM guideline.

1. Understand the change and why it is a required change.

2. Management is aware of it and approves.

3. Have the change planned at a time that has the least amount of impact on customers.

4. Have a back out strategy if things go wrong.

5. Document the change.

It is simply a matter of CYA, as may places will fire an admin implementing an unplanned chances, esp. when it has negative consequences.

mattsthe2

Ok I think we are digressing away from my original post.

Please understand that I'm lucky enough to have a full mock lab.
Even a separate test VLAN with our provider off of our DS3 so changes made will be fully understood and tested.

To go into a little more detail we have a lot of work at home employees who run VoIP to our Cisco CallManager over IpSec cisco router. They have cheap old regular DSL and i want to be a little bit more selective on the outbound ISP we use. Catch is that they dont have static IP's.

If you guys had 2 routers with two BGP - ISP's how would you configure it?

Just looking for some design ideas thats all...

mikej412

mattsthe2 wrote: »

If you guys had 2 routers with two BGP - ISP's how would you configure it?

Sample Configuration for BGP with Two Different Service Providers (Multihoming) [IP Routing] - Cisco Systems

Load Sharing with BGP in Single and Multihomed Environments: Sample Configurations [IP Routing] - Cisco Systems

Do you have your own IP Address space and Autonomous System Number?

You can also check out the Cisco Configuration Guides, Design Guides, and White Papers to find more examples for almost all BGP occasions.

networker050184

If you are looking to utilize both links at all times (and not an active - back up solution) then getting full routes would be the optimal solution. You can get full routes on the 3845 as they are upgradable to 1G and I believe Cisco recommends at least 512K to hold a full table.

If you just want to use one link and fail over to the other then defaults would be fine.

mattsthe2

networker050184 wrote: »

If you are looking to utilize both links at all times (and not an active - back up solution) then getting full routes would be the optimal solution. You can get full routes on the 3845 as they are upgradable to 1G and I believe Cisco recommends at least 512K to hold a full table.

If you just want to use one link and fail over to the other then defaults would be fine.

I was kicking around the idea of each edge router (remember one ISP circuit per edge router) installing a full BGP table but i didn't know if many customers are actually doing that.
I would love to see that happen - although the full BGP table would be installed in a VRF on that router.

I would then kick all my default traffic to Edge router 1 from my core switch and run iBGP between Edge Router 1 and Edge router 2 for the best ISP metric

Here is the sh ver, is the memory enough to handle that?

Cisco 3845 (revision 1.0) with 745471K/40960K bytes of memory.
Processor board ID ********
1 FastEthernet interface
2 Gigabit Ethernet interfaces
50 Serial interfaces
4 Channelized T1/PRI ports
1 Virtual Private Network (VPN) Module
1 Subrate T3/E3 port
DRAM configuration is 64 bits wide with parity enabled.
479K bytes of NVRAM.
500472K bytes of ATA System CompactFlash (Read/Write)

Configuration register is 0x2102

mattsthe2

mikej412 wrote: »

Sample Configuration for BGP with Two Different Service Providers (Multihoming) [IP Routing] - Cisco Systems

Load Sharing with BGP in Single and Multihomed Environments: Sample Configurations [IP Routing] - Cisco Systems

Do you have your own IP Address space and Autonomous System Number?

You can also check out the Cisco Configuration Guides, Design Guides, and White Papers to find more examples for almost all BGP occasions.

thanks for the link i will review.

Yes we have our own IP address space and AS number.