Set the MTU for Use in PMTU Discovery

1. Enter Global Configuration mode.

   SEFOS# configure terminal
   

2. Set the MTU value for use in PMTU discovery.

   SEFOS(config)# ipv6 path mtu 2004::0 1500
   

   where:

   • 2400::0 is the prefix address.

   • 1500 is the MTU value.

3. Use the ping command to connect to host B from switch 1 with the packet sizing as 1800.

   SEFOS# ping ipv6 fec0::3333:0:10 size 1800
    
   ping6 fec0::3333:0:10 1800 bytes of data
   1800 bytes from fec0::3333:0:10 : icmp_seq = 0
   1800 bytes from fec0::3333:0:10 : icmp_seq = 1
   1800 bytes from fec0::3333:0:10 : icmp_seq = 2
   1800 bytes from fec0::3333:0:10 : icmp_seq = 3
   1800 bytes from fec0::3333:0:10 : icmp_seq = 4
    --- Ping Statistics ---
   5 Packets Transmitted, 5 Packets Received, 0% Packet Loss
   

4. On switch 1, review the MTU value.

   SEFOS# show ipv6 pmtu
    
   PMTU discovery is enabled
    
     Ipv6 Path MTU Table
    -----------------
   Destination     PMTU
   -----------     ----
   fec0::1111:0:01200