TCP MSS adjustment for ESM hosts

This feature adds support for adjustment of the MSS size of TCP packets with SYN flag according to the access/aggregation network to prevent fragmentation of upstream and downstream TCP packets using ISA-BB diverted by IP/IPv6 filter actions.

The following ESM host types are supported:

• IPv4/IPv6 IPoE hosts

• locally terminated PPPoE hosts (without L2TP LAC)

• L2TP LNS hosts

The configuration steps are as follows:

1. Create a NAT group used for an MSS adjustment.

   config>isa
   nat-group 1
   active-mda-limit 2
   mda 1/1
   mda 1/2
   

2. Associate the NAT group with a routing instance and configure the MSS value.

   config>router
   config>service>vprn
   mss-adjust-group 1 segment-size 1452
   

3. Create an IPv4/IPv6 filter to perform an MSS adjust.

   config>filter>ip-filter>entry
   egress-pbr default-load-balancing
   match tcp-syn
   action tcp-mss-adjust
   config>filter>ipv6-filter>entry
   match tcp-syn
   action tcp-mss-adjust
   

4. Apply an IPv4/IPv6 filter to the SLA profile.