North American Network Operators Group|
Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical
Re: IP over SONET considered harmful?
> copying Tag-TTL into IP TTL. However, doing this introduces another > problem - it breaks traceroute. And there are enough folks in the MPLS > WG who think that the ability to traceroute through all the LSRs is an > "unalienated right". Without going to far into the traceroute source , would a solution to this problem be a modified traceroute that "understood" and could report Tag/MPLS "hops" as well as the normal method? There would need to be some way of identifying which devices were forwarding using Tag/Mpls and which were not, as well as getting and reporting the information. I think it falls into the same category of tracing cell forwarding in ATM without having access to the equipment doing the work. > In view of the above here are some of the possible avenues: > > (a) try to get "rough consensus" with the MPLS WG to allow > decrement IP TTL by 1 on egress (rather than copy Tag TTL > into IP TTL), or > > (b) talk to your favorite vendor(s), and ask the vendor(s) to put > a "knob" that would decrement IP TTL by 1 on egress (rather > than copying Tag TTL into IP TTL). Alan and I discussed the "knob" solution before, it seems to solve the problem, but under certain circumstances a packet could end up being forwarded forever because of (mis)configuration. -pee