• Status: Solved
  • Priority: Medium
  • Security: Public
  • Views: 445
  • Last Modified:

bgp implementation

Ok I will try to explain this as best as possible.

I'm a customer of provider (colo) that I receive bandwidth from.
I resale some of this bandwidth to numerous customers.
My latest customer is going to be using "multihome BGP" as they will be using the bandwidth we sold them as a backup connection for their branch offices/customer.

When they requested the AS and BGP peer information I was thrown for a loop.
So I asked my provider(colo) if they could handle this and we just pass this stuff transparently.
They said sure, but that we need to become capable of doing BGP peering within 6 months to prevent them from having to do with my future customers.

Now..Heres my question.
How do I become a bgp peer'able'?

I hope I explained all that correctly, please ask me anything if its not clear.

  • 5
  • 5
1 Solution
There are a few things.

You'll have to have your own IP space - last time I was involved in the process, you have to be able to justify your need for a /24 (at least)  to ARIN...which is no picnic. If you already have your own space, that helps a bit - but you still need to justify it.

You'll also need a router robust enough to handle the full inet routing table, if that's what you want to do. The last time I looked at a full BGP table handed out by a Tier 1 provider, it had about 150k routes - and that was over three years ago. It's probably closer to 200k routes today - and that's just for commercial internet. Internet2 has its own subset of routes as well.

If you're just acting as a pass-through so your customer can get routes from your upstream provider, then that might be simpler. You might be able to use private AS numbers to get the routes to propagate from your provider to your customer. Here's the thing, though - the reason your customer wants to multihome is they want to advertise *their* AS to your provider so traffic can reach them if their other pipe goes down. That's your deliverable, no matter what your method of getting it done. The AS announcement - or at least the routes - have to get through your router and propagated upstream.

What are you running today for a router?

spiz79Author Commented:
A Imagestream rebel series router
spiz79Author Commented:
and we have a /24

and I've given a /29 from that to this particular customer to use
Network Scalability - Handle Complex Environments

Monitor your entire network from a single platform. Free 30 Day Trial Now!

Okay, cool. Since your customer's IP space is a subset of yours, matters are somewhat simplified. You will announce your /24 to the world via BGP, which will include the IP space held by your customer. Since you own this space, though, you don't want your customer to announce that /29 out of their other connection, do you? That might mess up your own announcements to the world once your own BGP sessions are lit up.
spiz79Author Commented:
rharland, sorry I may be confusing you a bit as I'm confused and trying to wrap my head around all this.
I sure do appreciate all the help.

They have their own AS number and their own IP space that they will be announcing.

They are using one of the IPs from the /29 as their BGP IP...?

Ahhhhh....I'm sorry!
In that case, it should be a cakewalk. You'll announce your own /24 to the world, will accept your customer's AS into your BGP table, and will forward said AS information upstream to your provider. That's pretty straightforward!
As far as your Rebel router, marketing material places it to compete with Cisco 2x, 3x, and 7200 series routers - so I'd wager that it does BGP without a problem. If you turn up BGP on it and find the routing table is just too big, you still have some options on BGP routing table population. On Cisco boxes, you just use regular expressions to limit the routes accepted, etc....but that's another conversation.

spiz79Author Commented:
so my customer would become a peer?
would my upstream provider be a peer as well?

and I have given other customers some subnets off that /24...will advertising affect them at all?
Yes, you will have BGP sessions to both your customer and provider.

You will be providing the following information to your upstream provider via BGP.

1. Your AS and /24 associated with same.
2. Your customer's AS and their /24 associated with same.
This will populate your provider's routing table.

By establishing a BGP peering session with you, your customer will accomplish two goals:

1. They'll advertise their own /24 to the world via the connection to you (and by proxy your provider).
2. They'll get a full BGP routing table from you, if that's what they're after.

If you have other customers, they should not be affected by this new situation since they all reside inside of your supernet. They're downstream from you, so packets need to get to your router anyway - and once they're there BGP doesn't figure into the situation.

Your provider needs to peer with you because they need some method to get the BGP routes to your customer.

spiz79Author Commented:
Man thanks for that great explanation!
I think I can finally get to working on this thanks to your help.

And thanks for your time
No problemo....these are things I wish I had known when I set up BGP for the first time.
Question has a verified solution.

Are you are experiencing a similar issue? Get a personalized answer when you ask a related question.

Have a better answer? Share it in a comment.

Join & Write a Comment

Featured Post

Protect Your Employees from Wi-Fi Threats

As Wi-Fi growth and popularity continues to climb, not everyone understands the risks that come with connecting to public Wi-Fi or even offering Wi-Fi to employees, visitors and guests. Download the resource kit to make sure your safe wherever business takes you!

  • 5
  • 5
Tackle projects and never again get stuck behind a technical roadblock.
Join Now