ADTRAN 5000 Series - Manual (Page 1025)

Command Reference Guide Tunnel Configuration Command Set
61200990L1-35E Copyright © 2005 ADTRAN 1025
tunnel sequence-datagrams
Use the tunnel sequence-datagrams command to enable sequence number checking on incoming Generic
Routing Encapsulation (GRE) packets, to drop packets arriving out of order, and to include a sequence
number in outgoing packets. Use the no form of this command to disable sequence number checking.
Syntax Description
No subcommands.
Default Values
By default, this command is disabled.
Applicable Platforms
This command applies to the NetVanta 300, 1000R, 2000, 3000, 4000, and 5000 and Total Access 900
Series units.
Command History
Release 9.1 Command was introduced.
Functional Notes
Both ends of the tunnel must have sequence numbering enabled. When both endpoints have sequence
numbering enabled, a packet arriving with a sequence number less than the current expected value will be
dropped. If the endpoints differ in their sequence numbering configuration, all packets will still flow without
any sequence number verification. Be careful enabling sequence number verification on a tunnel. The
tunnel can easily become out of sequence due to network conditions outside of the tunnel endpoints. It
may be difficult to establish a successful traffic flow after an out of sequence condition occurs.
Technology Review
When enabled, the next valid sequence number will be placed in the GRE header of each outgoing packet,
and the sequence number present bit will be set.
Usage Examples
The following example enables sequence number processing on the tunnel interface:
(config)#interface tunnel 1
(config-tunnel 1)#tunnel sequence-datagrams