![route reflector route reflector](https://www.juniper.net/documentation/us/en/hardware/jrr200/images/g100081.png)
Probably to simplify the software code, Cisco announces ‘back’ all the routes received via iBgp or eBgp, even to the neighbor from which they are received. Here comes another interesting approach by Cisco: this doesn’t seem to depend on the switch/router family, nor on the software release.
![route reflector route reflector](https://reflector.sota.org.uk/uploads/db9433/optimized/3X/b/0/b010d1919812197b0ebb91ae9e5e1a0369f8713f_2_1380x712.jpg)
RR1 propagates the route to PE2 and PE1 (discarded by PE1 thanks to originator’s ID)įor this reason, every PE receives back and rejects (at least) a couple of bgp routes because they are reflected back two times by both RR, since they belong to different clusters.The same happens toward RR2 (not depicted above, but described here): cluster-id list (added by every RR which propagates an i-bgp route) originator ID (added by the first RR, it’s the bgp router id of the node that originated the route) To avoid loops in case of normal operation or misconfigurations, two parameters are used: Things can scale even to multiple RR layers, as depicted in Figure 3. Every client has an ibgp session with the RR belonging to the same cluster.
Route reflector full#
But what happens in case core P routers are redundant (as they always should be) ? Things should work like depicted in Figure 2: RR have a full mesh of ibgp session between them, and they also peer with all their clients. This is because those 4 RR are also a SPOF (Single Point Of Failure) for the network … hopefully, there is no real network made like this. In the above example diagram that has been found on the internet, the above questions can be easily answered: the network is divided into 4 different clusters, and the clients have an ibgp session with the RR belonging to the same cluster. how should ibgp sessions be established between clients and RR ? to which cluster-id should the RR belong ? If you don’t do nothing, the highest loopback address (at least on Cisco devices) is used (such as for the router id in many routing protocols). It has something to do with RR redundancy, and should be configured having in mind the consequences. A configuration parameter for route reflectors, which is very often ignored, is the “cluster id”.
![route reflector route reflector](https://1.bp.blogspot.com/-kpJdraHAEUk/XnI1J710pJI/AAAAAAAAGpo/E2lEhR5BLhs4TisiQHC0XBviEqZubhaAgCNcBGAsYHQ/s1600/Route%2BReflector.png)
They behave slightly differently from the standard bgp approach, breaking the ibgp split horizon rule: when they receive an ibgp route from a so called “route reflector client”, they propagate it to other ibgp clients and non clients (together with eBgp neighbors). To avoid this impact and huge amount of configurations, Route Reflectors are used to better scale the network. We invite you to schedule a call with one of our subject-matter experts who can answer your questions and provide more information about the MEX-IX, the only peering platform focused on Mexico.Due to the need of having the same knowledge of the network and routing information, PE routers on an mpls network require a full mesh of ibgp sessions. Peering doesn’t have to be complicated, here at MDC we want you to enjoy the benefits of being part of an internet exchange without hassle. If you decide to join only the route collector, then you will have to establish peering with each network individually. Unlike route collectors, connecting to a route server is optional. One connection enables traffic exchange with all participants peering with the route server. This is where route servers come in.īy connecting to a route server, there is no need to establish individual BGP sessions with each network on the contrary, the route server allows for multilateral peering. As the number of connected parties increases, it becomes harder to manage these relationships. In order for IXP participants to exchange traffic, they have to establish bilateral peering relationships (BGP sessions) with each other. Lastly, connecting to a route collector is mandatory to join an IXP. Prospective members then use this information to assess the value of joining and it helps existing members test their BGP configurations.įor IXPs themselves, route collectors are essential for diagnostics and to collect metrics. Route collectors strictly run BGP and are necessary to create a public view of the routing information and members’ peering policies available at an IXP. While it does “collect” routing information it does not forward packets or broadcast routing prefixes. The most important FAQs about peering in Mexico What is a route collector?Īs the name suggests, the main function of route collectors is to gather information on each network connected to an IXP.