ICMP: Extension

We've implemented RFC 5837, Extending ICMP for Interface and Next-Hop Identification, for both numbered and unnumbered aggregated Ethernet interfaces. We can now append additional fields to the following ICMP (IPv4 and IPv6) messages:

• ICMPv4 Time Exceeded
• ICMPv4 Destination Unreachable
• ICMPv6 Time Exceeded
• ICMPv6 Destination Unreachable Use the set system allow-icmp4-extension command to enable ICMP extension.