[c-nsp] Is this a bug or is it just me not understanding something?

[Ted Mittelstaedt]

Hi All,

  I have a 7206 router that has a PA-A3-3 card in it running IOS 12.2.46a

The router has the following config snippit in it:

interface ATM1/0.2 multipoint
 description NEW Qwest DSL
 no ip route-cache
 no ip mroute-cache
 pvc 5555555555 1/56
  vbr-nrt 896 896 120
 !
 pvc 5555555556 1/98
  vbr-nrt 1600 1600 120
 !
etc.

It's been working fine for some time.


Anyway, as we know Cisco released the
Multiple Features Crafted UDP Vulnerability
so I tried loading  IOS 12.2.33.SRD1  on it
to fix the vulnerability.

Everthing seemed to work except that the
new IOS bitched about the vbr-nrt statements.

If I changed the snippit above to:


interface ATM1/0.2 multipoint
 description NEW Qwest DSL
 no ip route-cache
 no ip mroute-cache
 pvc 5555555555 1/56
  vbr-nrt 896 896 1
 !
 pvc 5555555556 1/98
  vbr-nrt 1600 1600 1
 !
etc.


it works.  I tried running command line help and this is what i got:

router(config-if-atm-vc)#vbr-nrt ?  
  <1-44209>  Peak Cell Rate(PCR) in Kbps

router(config-if-atm-vc)#vbr-nrt 320 ?
  <1-320>  Sustainable Cell Rate(SCR) in Kbps

router(config-if-atm-vc)#vbr-nrt 320 320 ?
  <1-1>  Maximum Burst Size(MBS) in Cells
  <cr>

Why is the IOS suddenly not allowing MSB's larger than 1?

Ted