[j-nsp] Netscreen firewalls & multicast replication

Phil Mayers p.mayers at imperial.ac.uk
Thu Jun 17 08:54:47 EDT 2010


All,

Just a quick question...

We run a pair of Netscreen 5400s with M2 management boards and 10gig 
modules, running ScreenOS 6.3, in routed mode.

A while back we discovered a documented limitation, specifically that 
these firewalls don't have multicast replication hardware. You can run 
them in one of two modes:

  1. Multicast is done in hardware. In this mode, receivers must all be 
on one outbound interface, and multicast is "faked", I guess by adding 
/32 routes for the group pointing out of the output interface (as 
opposed to a "proper" 64-bit (s,g) lookup) - this is "set flow multicast 
install-hw-session".

  2. Multicast is done in software. In this mode, things work as normal 
but very high bit rates (e.g. a 20Mbit stream) can load the CPUs. This 
is the default.


So, this is unfortunate but fine - I can live with that.

Question: do any later models of Juniper/Netscreen have multicast 
replication hardware?

Do any other *vendors* have it?

Obviously transparent / layer2 mode doesn't have this issue, but we 
don't want to run that for many reasons.


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