satz@cisco.com (Greg Satz) (06/24/91)
You mention that MTU discovery can take a short cut when used in conjunction with cisco routers running IGRP as the information is present in the closest router. This is true. Unfortunately the world is not made up of cisco routers alone. There is no guarantee nor is it probable that the complete path (or set of paths) will traverse a single vendor's router. The IETF implemented a generic MTU discovery mechanism that will work regardless of routing protocol and vendor. This is a requirement of the IETF. The MTU discovery working group was sensitive to offered load of their protocol and documented when it should be used to minimize wasted bandwidth. What you point out is an enhancement we could make as a value added feature in a future release of our software. Greg
rene@geveke.nl (Rene van der Hauw) (06/24/91)
Dear people of the internet / people of cisco At the Technical conference in Stockholm/Helsinki, cisco explained the way the Router Discovery Protocol was implemented in the Terminal Server. Good Job! I haven't worked before with this protocol, so I was supprised that this protocol was using the mtu. It was used to find the lowest mtu value. The only way to find this value, is by going through the entire network until the final network is reached. Is this also necessary when using cisco routers? When looking at IGRP, cisco is sending the mtu already with there routing data. So why hitting everytime a router before knowing the lowest mtu? Isn't it possible to supply this information when the packet is hitting the first cisco router, because the data is already in the routing table! By doing this, you will see less data going through your entire network, this can be important when looking at large WAN's with small bandwidth. And it will be more important if more vendors are going to use this protocol!!! This could another good reason to use IGRP!!!! Looking forward reply. Rene van der Hauw Geveke electronics The Netherlands +31 20 5675558