Your right - it’s a broken L2. Only routers are supposed to decrement TTLs. Links and tunnels themselves aren’t.
Joe > On Dec 6, 2018, at 5:16 AM, Stewart Bryant <[email protected]> wrote: > > > >> On 06/12/2018 05:22, Joe Touch wrote: >> >>> On Dec 5, 2018, at 9:01 PM, Christopher Morrow <[email protected]> >>> wrote: >>> >>> How is it, for example, different to put ipv6 packets into an MPLS path >>> doing nothing along 'many' hops (except forwarding the packets along), and >>> then once you pop out of the tunnel start processing the packet as you >>> (joe) would want. >> The hopcount doesn’t get decremented by L2. >> >> Joe > > MPLS is not L2. > > MPLS has two modes, one in which the TTL of the IP payload is decremented on > ingress and the TTL across the MPLS path is ignored. In the other mode, the > TTL of the IP packet minus one is copied into the MPLS label which is then > decremented as the packet travels across the network at egress from the MPLS > layer the TTL is copied back into the the IP packet. > > - Stewart _______________________________________________ OPSEC mailing list [email protected] https://www.ietf.org/mailman/listinfo/opsec
