[c-nsp] Sup2T refuses to erspan

[Sebastian Beutel]

Dear List,

    the other day i needed to erspan from one of our routers. I set up my
erspan session as allways but this time when i typed "no shut" i got this:

---<snip>---

router(config-mon-erspan-src)#no shutdown 
% Supervisor hardware has been disabled for ERSPAN.

---<snip>---

I can't find anything about this. Neither in Bug Search nor in the
Documentation. I only have a faint idea of what the reason could be: For
historical reasons there is an mtu of 9216 configured on this router.
Documentation states that ERSPAN supports only Layer 3 packets of up to 9202
bytes but also, that L2 frames are truncated to fit into this packet size.
Not, that ERSPAN is dissabled entirely. Has anyone seen something like this? 

Hardware is a dual VS-SUP2T-10G running 15.2(1)SY5 and this is what i have 
in running configuration (and can't noshut):

!
monitor session 1 type erspan-source
 shutdown
 source vlan 500
 destination
  erspan-id 42
  ip address a.b.c.d
  origin ip address d.c.b.a
!

Best,
   Sebastian.