If you have enabled PMTUD under the tunnel interface, it seems odd that it is not working. Is your network blocking the ICMP fragmentation needed messages from the upstream router? However, another option is to manually lower the MTU under the [edit interfaces gr-x/x/x unit 0 family (inet|inet6|etc)] hierarchy to account for times when the resilient link is in use. You would need to lower it on both ends of the tunnel. And, this would be slightly suboptimal in that it would potentially cause fragmentation of large packets when none is needed; however, at least they should get through.
HTHs -Jon On 2/1/07, [EMAIL PROTECTED] < [EMAIL PROTECTED]> wrote: > > I currently use a GRE tunnel to transit traffic from one site to > another. However, this tunnel traverses another network which also uses > a GRE tunnel to transport their traffic over their resilient path. > I do know when using our GRE tunnel over the providers native primary > link, there are no problems. When traffic traverses the resilient link > (GRE over GRE) large packets do not get through. > All routers are setup to use PMTUD and given that the routers are using > the built in tunnel interface I believe setting the TCP MSS value is not > achievable. > > Does anyone know a work around to this problem? > > Regards, > > Laura McDonnell > > Network Analyst > > Canterbury Christ Church University > North Holmes Road > Canterbury > Kent > CT1 1QU > > Tel: +44 (0) 1227 782945 > Email: [EMAIL PROTECTED] > http://www.canterbury.ac.uk > http://www.kentman.ac.uk > > > > _______________________________________________ > juniper-nsp mailing list juniper-nsp@puck.nether.net > https://puck.nether.net/mailman/listinfo/juniper-nsp > _______________________________________________ juniper-nsp mailing list juniper-nsp@puck.nether.net https://puck.nether.net/mailman/listinfo/juniper-nsp