Path Mtu Discovery - Dell Force10 S4810P Configuration Manual

Path MTU Discovery

IPv6 MTU Discovery
Path MTU (Maximum Transmission Unit), in accordance with RFC 1981, defines the largest packet size
that can traverse a transmission path without suffering fragmentation. Path MTU for IPv6 uses ICMPv6
Type-2 messages to discover the largest MTU along the path from source to destination and avoid the need
to fragment the packet.
The recommended MTU for IPv6 is 1280. Greater MTU settings increase processing efficiency because
each packet carries more data while protocol overheads (headers, for example) or underlying per-packet
delays remain fixed.
Figure 25-2. MTU Discovery Path
Source
MTU
Packet (MTU
ICMPv6 (Type 2)
Use MTU
Packet (MTU
ICMPv6 (Type
Use MTU
Packet (MTU
is supported on platforms
Router A
1600 MTU
1600)
1400
1400)
2)
1200
1200)
Packet Received
c e s z
Router B
1400 MTU
Destination
1200
IPv6 Routing | 547