Dedicated Route Reflectors
Hello, We're in the process of planning for an MPLS network that will use BGP for signaling between PEs. This will be a BGP free Core (i.e. no BGP on the P routers). What are folks doing for iBGP in this case? Full Mesh? Full Mesh the Main POP PEs and Route Reflect to some outlining PEs? Are folks using dedicated/centralized Route Reflectors (redundant of course)? What about using some of the P routers as the Centralized Route Reflectors? The boxes aren't doing much from a Control Plane perspective, why not use them as Route Reflectors. Any comments would be appreciated. Thanks, Serge __________________________________________________________________ Looking for the perfect gift? Give the gift of Flickr! http://www.flickr.com/gift/
Hi there The RR vs Full Mesh depends on what how you would like to balance your exit/peering points across the network. If you have, say, 3 border routers in 3 different regions, you should need at least 3 RRs if you want each region having it's own preference for the external routes. I would advise Full Mesh if the equipments can manage the number of iBGP sessions and update-groups are quite fast this days, also the management overhead is not much of an issue as "advertised". About keeping the P routers as RR, I think that is will load the FIB with useless external routes, and keeping them in a VRF is not quite OK, depending on the used platform. Pavel. Serge Vautour wrote:
Hello,
We're in the process of planning for an MPLS network that will use BGP for signaling between PEs. This will be a BGP free Core (i.e. no BGP on the P routers). What are folks doing for iBGP in this case? Full Mesh? Full Mesh the Main POP PEs and Route Reflect to some outlining PEs? Are folks using dedicated/centralized Route Reflectors (redundant of course)? What about using some of the P routers as the Centralized Route Reflectors? The boxes aren't doing much from a Control Plane perspective, why not use them as Route Reflectors.
Any comments would be appreciated.
Thanks, Serge
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On 11 Sep, 2009, at 09:30, Serge Vautour wrote:
Hello,
We're in the process of planning for an MPLS network that will use BGP for signaling between PEs. This will be a BGP free Core (i.e. no BGP on the P routers). What are folks doing for iBGP in this case? Full Mesh? Full Mesh the Main POP PEs and Route Reflect to some outlining PEs? Are folks using dedicated/centralized Route Reflectors (redundant of course)? What about using some of the P routers as the Centralized Route Reflectors? The boxes aren't doing much from a Control Plane perspective, why not use them as Route Reflectors.
serge, you can, and probably should, segment your mpls signalling ibgp from your internet/peering ibgp. in other words, on your pe, you configure ipv4/ipv6 bgp sessions to your peering/transit routers, then you configure mp-bgp sessions to three or four mpls vpn route reflectors. the mpls route reflectors do not participate in the actual routing of any packets (they don't set next-hop-self, only the pe routers would), their only function is to reflect the vpn signalling between disparate pe boxen. similarly, if you have a very large number of pe routers, you can setup three or four boxes to reflect internet/customer routes...these boxes also would not route any packets, they would just reflect the non-mpls bgp sessions (they don't set next-hop-self, only the pe/ transit/peering router do). alternately, if you have local transit/peering routers at every pe site, then you can mesh all the transit/peering routers and have the local pe routers be rr clients of that site's transit/peering routers hth /joshua
Hi, I have seen networks use the control plane of large P routers to reflect their inet-vpn routes. Keep in mind that when reflecting inet- vpn routes, the next-hops need to be "reachable". So quite possibly you will need some policy to resolve the MPLS next-hops. Internet / VPN / and now IPv6 peers have different growth rates, so you may benefit in having different "types of route reflectors" for different address families. In a small PE deployment (say, 5-50) PE nodes, you can deploy the route reflection on your P routers. Create some redundancy, and have your PE nodes peer with 2-3 of them. It keeps the configuration much smaller that having to define all the neighbours in a full mesh. When you have lots of routes and PEs, you can start to have dedicated RRs for different address families. Truman On 12/09/2009, at 1:30 AM, Serge Vautour wrote:
Hello,
We're in the process of planning for an MPLS network that will use BGP for signaling between PEs. This will be a BGP free Core (i.e. no BGP on the P routers). What are folks doing for iBGP in this case? Full Mesh? Full Mesh the Main POP PEs and Route Reflect to some outlining PEs? Are folks using dedicated/centralized Route Reflectors (redundant of course)? What about using some of the P routers as the Centralized Route Reflectors? The boxes aren't doing much from a Control Plane perspective, why not use them as Route Reflectors.
Any comments would be appreciated.
Thanks, Serge
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Hi, There are multiple ways you can solve that problem. We do the following: 1. Each region has its own ibgp cluster with 2 route reflectors (usually the P nodes, since they seem to have abundance of CPU power and not much to do with it). 2. All route reflectors (across regions) are fully meshed. We thought a bit about creating two 'super' route servers, but then then number of adjecencies is not that big ( we only have a few regions ). Regarding internet traffic - we keep the Internet in a VPN, all PEs that host that VPN are fully meshed and advertise only a default to the common route reflectors (in their corresponding regions). Each internet PE uses different RD, so there are multiple default routes present in the regions. kind regards Pshem 2009/9/12 Serge Vautour <sergevautour@yahoo.ca>:
Hello,
We're in the process of planning for an MPLS network that will use BGP for signaling between PEs. This will be a BGP free Core (i.e. no BGP on the P routers). What are folks doing for iBGP in this case? Full Mesh? Full Mesh the Main POP PEs and Route Reflect to some outlining PEs? Are folks using dedicated/centralized Route Reflectors (redundant of course)? What about using some of the P routers as the Centralized Route Reflectors? The boxes aren't doing much from a Control Plane perspective, why not use them as Route Reflectors.
Any comments would be appreciated.
Thanks, Serge
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participants (5)
-
joshua sahala -
Pavel Stan -
Pshem Kowalczyk -
Serge Vautour -
Truman Boyes