[j-nsp] EX3300/EX4300 Licensing

Jeff Wheeler jsw at inconcepts.biz
Wed Nov 20 05:20:52 EST 2013

On Mon, Nov 18, 2013 at 12:45 PM, James Jun <james at towardex.com> wrote:
> BCP38 at customer ports as best practice.  Requiring a paid license to
> enable sommething as simple as uRPF is Juniper's contribution to further
> help discourage BCP38 implementation, imo.

uRPF on the small-EX switches has problems that go beyond licensing.

When last I checked, you could only enable or disable it globally,
even though Junos lets you configure it on an individual
port/interface.  If it is enabled and the switch has dual uplinks to
your distribution / core which are on different interfaces ... it will
just urpf-fail all traffic arriving from the uplink interface that
isn't the current best-path for 0/0.

Because it also won't do MPLS on SVI/RVIs, only on layer-3 ports, you
can't design around this problem by using an SVI for your dual-homed
layer-3 uplink and relying on STP to provide connection to two
upstream devices on a single IFL, using a shared uRPF "filter."
Unless, of course, you choose between either MPLS services or layer-3
services and don't mix them together in a stack.

Basically, IMO, Juniper takes some great liberties when they claim
these switches "support" "uRPF."
Jeff S Wheeler <jsw at inconcepts.biz>
Sr Network Operator  /  Innovative Network Concepts

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