I had a feeling that would happen, I will try to clarify. I was not trying to say that there should be a central core site for the ISP's entire network, but for pieces of it. Lets take a state like New York, within it you have 3 POPs, each is in it's own AS and runs an IGP. In each POP you have 2 core routers and 3 aggregation routers, the 2 core routers have EBGP connections and are reflectors for the 3 aggregation routers. Now you want all 4 POPs to be in the same AS, and they have to have direct connectivity to your 3 New Jersey POPs which should also be in the same AS. In that case, would it make sense to choose a NY POP and a NJ POP, install 2 core or backbone routers that do not participate in any IGP, use those to peer with the POPs in that state and in turn peer with the other state's core or backbone routers? This would significantly reduce the amount of peering that would be required. Hopefully the drawing won't be a disaster.
NY POP 1 NJ POP 1 o o o o o o o o o o NY POP 2 NJ POP 2 o o o-------------------o o o o \ / o o o / \ o o o-------------------o NY POP 3 NJ POP 3 o o o o o o o o o o -----Original Message----- From: Phillip Heller To: [EMAIL PROTECTED] Sent: 7/10/2002 7:33 PM Subject: Re: Route Reflection with Multiple POPs [7:48509] On Wed, Jul 10, 2002 at 10:27:08PM +0000, Lupi, Guy wrote: I know that you can run confederations and reflectors, and seperate levels of reflection, which Cisco refers to as "nested reflection". Now my question is, how would you set up your bgp peering? Due to financial constraints I would imagine that the best thing to do would be to have one circuit from POP router 1 to core router 1, and another circuit from POP router 2 to core router 2. Assuming that you are only running BGP in the core, and that the clients have to have a session with each reflector, how would you communicate the loopback addresses of all the routers to each other? Are static routes used in this situation? Thanks to all of the people who responded by the way, I appreciate the direction. Ever feel like you know so much, only to read a book and find out that you know so little :)? I hate to say it, but the question is somewhat ambiguous and confusing... First and foremost, what is the physical topology of your backbone? How many devices are you dealing with? These days, most large service provider networks are of a partial mesh (physical) design. There is no central "core" site. Each pop has several aggregation boxes and several "core" boxes. The core boxes connect to each other and to other pop's core boxes. Also, the core boxes provide connections for the aggregation boxes. While it's common to see route-reflection from the core to aggregation boxes, it's less common to see route-reflection from one pop to other *multihomed* pops. Generally, customers maintain one bgp session per physical connection to the network; further, the bgp sessions are generally between the directly connected devices. Sometimes customers will want to bond multiple equal bandwidth paths. In this instance, customers generally have less than one bgp session per physical connection (ie: ebgp-multihop with static routes and cef, or Multilink PPP). --phil Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=48565&t=48509 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]