[j-nsp] Junipers and broadcast storm issues

[Mark Johnson]

Hi,

I'm a little disappointed so far in the way my M7i's handle broadcast storms 
at peering points. I'm hoping someone on the list could enlighten me if this 
is normal or if I can improve my config.

Previously, with Cisco 7200 routers, I have seen increased CPU on the router 
during such events but it has never impacted traffic flowing through the 
router.

The first broadcast storm was when an IXP's link went unidirectional. It was 
a FE port. Our monitoring system showed that a few ping tests that went 
through the affected router were dropped. I raised a ticket with Imtech who 
provide support but couldn't provide any reason for packets passing through 
the router to be dropped. They just pointed out that all the packets 
arriving would need to be processed by the RE and this might max out the RE 
or the link to the RE.

The second storm was on a GigE port when an IXP had a port looped by a 
member. The event was a little longer than the first one and the effects a 
bit more severe. MRTG 5 minute average showed that the port received about 
70Mb/s and 140kpps. MRTG also showed that the RE/FE CPU utilisation only 
increased marginally and stayed below 20%.

Our monitoring system showed that traffic flowing through the router was 
degraded. The routers logs showed no OSPF or BGP drops (other than those to 
the affected IXP) and there were no other entries whatsover in the router's 
log.

Any advice appreciated.

Kind regards,

Mark