Command Reference Guide Tunnel Configuration Command Set61200510L1-35E Copyright © 2005 ADTRAN 1160tunnel sequence-datagramsUse the tunnel sequence-datagrams command to enable sequence number checking on incoming GenericRouting Encapsulation (GRE) packets, to drop packets arriving out of order, and to include a sequencenumber in outgoing packets. Use the no form of this command to disable sequence number checking.Syntax DescriptionNo subcommands.Default ValuesBy default, this command is disabled.Applicable PlatformsThis command applies to the NetVanta 300, 1000R, 2000, 3000, 4000, and 5000 and Total Access 900Series units.Command HistoryRelease 9.1 Command was introduced.Functional NotesBoth ends of the tunnel must have sequence numbering enabled. When both endpoints have sequencenumbering enabled, a packet arriving with a sequence number less than the current expected value will bedropped. If the endpoints differ in their sequence numbering configuration, all packets will still flow withoutany sequence number verification. Be careful enabling sequence number verification on a tunnel. Thetunnel can easily become out of sequence due to network conditions outside of the tunnel endpoints. Itmay be difficult to establish a successful traffic flow after an out of sequence condition occurs.Technology ReviewWhen 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 ExamplesThe following example enables sequence number processing on the tunnel interface:(config)#interface tunnel 1(config-tunnel 1)#tunnel sequence-datagrams
