[j-nsp] J series packet mode

Phil Mayers p.mayers at imperial.ac.uk
Thu Dec 19 09:39:47 EST 2013

On 19/12/13 14:25, Tom Storey wrote:
> Hi everyone.
> Whats the general consensus about using a J series entirely in packet
> mode?

We do it with no problems on both J-series and branch SRX (210H, FWIW).

Some people are annoyed about the amount of RAM consumed (wasted) by 
starting the flow daemon. Whether that matters will depend on how much 
RAM you need.

> Are there any gotchyas to be wary of, like missing features,

Basically anything flow-related; no ipsec, etc.

> performance hit? It looks like you can configure 3 address families
> for packet mode (iso, inet6, mpls) but not inet4. But, from what Im
> reading, enabling MPLS packet mode forces the whole box in to packet
> mode, including inet4.


> FWIW the situation I am picturing would not require NAT or IPSEC or
> other services like that, just packet shifting with ACLs, some
> routing protocols (IS-IS/BGP), and something like VRRP for gateway
> redundancy.

This is exactly what we do, with MPLS L3VPN and PIM multicast on top. It 
works fine.

> As I understand it the J series were originally a packet mode box
> until Juniper switched the default behaviour to flow based. Has
> there been any major architecture changes that would rule out packet
> mode operation?

Not as far as I'm aware; current JunOS on our J-series is 11.4R7.5 and 
we're running packet-mode no problems.

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