[Xorp-users] RTT "Round Trip Time"

Gernot W. Schmied gernot.schmied@chello.at
Wed, 11 May 2005 15:21:55 +0200

Pavlin Radoslavov wrote:
>>I'm a graduate student and my graduate project about "Round Trip Time"
>>as router matrix. So I think to use XORP as my research environment.
>>But I notice that the default xorp RIP matrix is "Hob Count". So does
>>any one has any idea how I can make it RTT "Round trip time"? any help
>>or suggestions in this subject or previous experience?
> Tariq,
> The RIP protocol itself is designed to use hop-count, so it is not
> clear whether it can easily be modified to use RTT instead of
> hop-count. It may be simpler to design your own routing protocol
> that uses RTT instead of modifing RIP, but you should be the one to
> research that option :)
> Once you have designed your routing protocol, then you can decide
> whether you can reuse some of the RIP code.
> If you want to implement your protocol from scratch, then you can
> use the static_routes implementation as a starting point.
> Good luck!
> Atanu & Pavlin
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Designing a routing protocol around a volatile, largely varying and
intrinsically unpredictable metric such as RTT is a difficult task and
generally not a good idea in a best-effort IP network. I'd rather
suggest you take an existing routing protocol such as OSPF or EIGRp and
consider implementing the generic "cost" hook based on consolidated RTT
data instead of bandwidth, hop-count or something else. Anyway, you have
to consider the return-path as well so that would defeat the purpose.
For a start you could also look at the EIGRP hybrid metric approach.