To reassemble GRE SDP tunnel fragments on the node terminating the service carried in the GRE SDP tunnel, the BB-ISA application is used to receive fragments, reassemble them, and return the reassembled GRE SDP tunnel packet for regular ingress processing.
To enable reassembly of GRE SDP fragmented packets, the following items must be configured:
Enable the BB-ISA application on the node (see the 7450 ESS, 7750 SR, and VSR Multiservice Integrated Service Adapter and Extended Services Appliance Guide for more information).
Configure an IP filter, using config>filter>ip-filter with:
default-action forward
match protocol gre and fragment set to true
action set to reassemble
Configure a NAT group under config>isa>nat-group with the active-mda-limit set to 1 and referencing the mda where the BB-ISA is configured.
Add the filter to the router interface or interfaces where GRE SDP packets and fragments are expected to be received.
Enable reassembly to base routing by configuring config>router>reassembly group nat-group to-base-network.
For example:
#--bb-isa----------------------------------------------
config
card 1
mda 2
mda-type isa-bb-v
no shutdown
exit
no shutdown
exit
#--ip-filter----------------------------------------------
filter
ip-filter 10 create
default-action forward
entry 1 create
match protocol gre
fragment true
exit
action
reassemble
exit
exit
exit
exit
#--nat-group----------------------------------------------
isa
nat-group 1 create
active-mda-limit 1
mda 1/2
no shutdown
exit
exit
#--router-base--------------------------------------------
router Base
interface "system"
address 91.91.91.91/32
no shutdown
exit
interface "to-PE2"
address 61.61.61.61/24 gre-termination
port 1/1/11:123
ingress
filter ip 10
exit
no shutdown
exit
exit
exit