route server

[amms68958]

Hi,

Just have a doubt about the concept of route server..What is the significance of a route server in an ISP..? I have read that route server is typically used with eBGP neighbors..whether the route server do the same function a Route reflector do with IBGP peers..?

Thanks in advance,

Thomas.

[mark.mcsherry]

Hi Thomas,

Do you mean a route server in terms of DNS?

For ISPs, they will generally run their own name servers, but these are not authoritive for all domains. They must do recursive lookups for domains they don't know about and for this they will go to the route servers.

The route servers will redirect their request to the appropriate DNS server on the next level down, until the authoritive server is located.

Route reflectors are a BGP design which allows you to avoid having to build a full mesh.

HTH,

Mark

[Kevin Dorrell]

Aren't the DNS things root servers?

[Richard Burts]

I do not think that the original question was really about DNS. Especially in a BGP/ISP context a route server is generally understood to be a device (might be a router or might be some other kind of box) that participates in BGP, is generally available to people outside the organization that runs the route server, and allows one to see the contents of the Internet routing table. They are not at all related to route reflectors.

There are a number of ISPs who provide this as a service to their customers and other members of the Internet community.

For a very extensive listing of route servers you can look at http://www.traceroute.org.

HTH

Rick

[amms68958]

Mark/Kevin,

Thanks for your replies..Sorry that my question was not specific..I asked abt BGP route servers..Infact,I didnt know that there is something called DNS route/root servers,and I learned it from your posts..

Rick,

Thanks for your reply.Till yesterday,my concept abt route server was the same as you mentioned until I came across some lines in Cisco Press book Advanced IP network design.(page No.212)

"Sometimes Route reflectors are confused with Route Servers.Route servers are generally used at Internet exchnaghe points.The objective of the routers to only peer with the route server and obtain the routing information from it.The route server has the capability of propogating info in a transparent fashion-as if the advertisements were received directly from the router originating it.Route reflectors also try to reduce the number of peers needed in an ibgp cloud,where as route server is typically used with ebgp neighbors.THe route server itself process no traffic,where as route reflectors do.It is clear that route reflectors and route servers staisfy different needs in the network."

Can you pls explain the above lines.?

Thanks in advance,

Thomas.

[marikakis]

When your posting arrived I was about to send the following:

"Route servers were not conceived in the first place to be a tool/service for customers.

The main goal had been to reduce the peering sessions on peering points.

Instead of a router peering with all other routers, it would only peer with the route server.

The route server would not be in the forwarding path,

while RRs are generally in the forwarding path.

(RRs can be removed from the forwarding path.

Have a look at Harold saying nice things (as usual):

http://forum.cisco.com/eforum/servlet/NetProf?page=netprof&CommCmd=MB%3Fcmd%3Dpass_through%26location%3Doutline%40%5E1%40.1dd72d5b/6#selected_message )"

What I had been writing is very similar to the text you posted ;-)

It's a bit hard for me to explain further,

because I can't see any misunderstanding in what you have written up to now.

(Are you sure you do not understand it ? :-)

I can only further say the following:

In an Internet eXchange Point the sessions between peers are eBGP.

Imagine N routers with agreement to peer with one another in an IXP.

Each router would need N-1 eBGP sessions [ total: (N-1)*N/2 ].

If we put a route server "in the middle",

each router has only 1 eBGP session with the route server [total: N].

As far as I know, route servers have not generally been much of a success

regarding their initial goal.

M.

[amms68958]

hi maria,

Thanks for your reply.it really helps..Infact,my first posting is whether the route server will behave same (in case of ebgp peers) as a route reflector behaves in case of ibgp peers..I quote the book to substantiate my question in the first posting..

Thanks agian for your explanation..