[j-nsp] juniper-nsp Digest, Vol 132, Issue 17

[venkatesh dangar]

Hi Clarke,

100 pps should not be a big thing. Have you configured IGMP snooping?

Regards,
Venkatesh


On Wed, Nov 13, 2013 at 10:30 PM, <juniper-nsp-request at puck.nether.net>wrote:

>  [image: Boxbe] <https://www.boxbe.com/overview>
> juniper-nsp at puck.nether.net is not on your Guest List<https://www.boxbe.com/approved-list?tc_serial=15658474272&tc_rand=2009934254&utm_source=stf&utm_medium=email&utm_campaign=ANNO_MWTP&utm_content=001&token=A0Np1I6Z6K5dcT5G%2BnShTxWU2IO6JMOCBTgGipBQvMAsAkvjnw%2BCy85AIjNcHJ7G&key=Dkun%2FGqZnRcYVDmrYgQp1DDbKeg6LOWTRVtxZt%2FHA0Y%3D>| Approve
> sender<https://www.boxbe.com/anno?tc_serial=15658474272&tc_rand=2009934254&utm_source=stf&utm_medium=email&utm_campaign=ANNO_MWTP&utm_content=001&token=A0Np1I6Z6K5dcT5G%2BnShTxWU2IO6JMOCBTgGipBQvMAsAkvjnw%2BCy85AIjNcHJ7G&key=Dkun%2FGqZnRcYVDmrYgQp1DDbKeg6LOWTRVtxZt%2FHA0Y%3D>| Approve
> domain<https://www.boxbe.com/anno?tc_serial=15658474272&tc_rand=2009934254&utm_source=stf&utm_medium=email&utm_campaign=ANNO_MWTP&utm_content=001&dom&token=A0Np1I6Z6K5dcT5G%2BnShTxWU2IO6JMOCBTgGipBQvMAsAkvjnw%2BCy85AIjNcHJ7G&key=Dkun%2FGqZnRcYVDmrYgQp1DDbKeg6LOWTRVtxZt%2FHA0Y%3D>
>
> Send juniper-nsp mailing list submissions to
>         juniper-nsp at puck.nether.net
>
> To subscribe or unsubscribe via the World Wide Web, visit
>         https://puck.nether.net/mailman/listinfo/juniper-nsp
> or, via email, send a message with subject or body 'help' to
>         juniper-nsp-request at puck.nether.net
>
> You can reach the person managing the list at
>         juniper-nsp-owner at puck.nether.net
>
> When replying, please edit your Subject line so it is more specific
> than "Re: Contents of juniper-nsp digest..."
>
>
> Today's Topics:
>
>    1. EX cpu performance under multicast replication load?
>       (Clarke Morledge)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Wed, 13 Nov 2013 11:33:57 -0500 (EST)
> From: Clarke Morledge <chmorl at wm.edu>
> To: juniper-nsp at puck.nether.net
> Subject: [j-nsp] EX cpu performance under multicast replication load?
> Message-ID: <alpine.GSO.2.00.1311131119130.27690 at stat.wm.edu>
> Content-Type: TEXT/PLAIN; format=flowed; charset=US-ASCII
>
> I am seeing some bothersome CPU performance issues on EX switches, mostly
> on the less powerful units like the 2200s, when it comes to handling
> multicast.
>
> In practical situations, I do not see much multicast traffic in general,
> except on our campus we do get a lot of Apple Bonjour traffic related to
> Multicast DNS.  Sometimes, a single host will go a little bonkers with
> repeated MDNS packets.   In one case, I have seen where a flood of about
> 100 multicast packets per second, related to Bonjour, will cause the CPU
> on the lower end EX switches to spike up dramatically, resulting in loss
> of management of the switch during peak loads.   For example, the switch
> will stop handling ICMP echo requests to its management IP, or it will
> miss RADIUS packets.
>
> Can someone walk me through the EX architecture a bit to tell me if this
> is expected behavior?  I am assuming the EX CPU is actually handling the
> multicast replication of Ethernet frames received to be sent out other
> ports, but it seems like 100 packets per second should not be a big deal
> to worry over.  So something looks awry.
>
> Oddly enough, I do not see any performance issues when straight-up
> broadcast traffic hits these kind of packet rates.
>
> To mitigate against this, I guess I could use QoS to prioritize management
> frames over user multicast data, but if the issue is about packet
> replication and not forwarding, I am entirely convinced that the standard
> marking and handling QoS parameters would be effective.
>
> Any ideas?
>
> Clarke Morledge
> College of William and Mary
> Information Technology - Network Engineering
> Jones Hall (Room 18)
> Williamsburg VA 23187
>
>
> ------------------------------
>
> Subject: Digest Footer
>
> _______________________________________________
> juniper-nsp mailing list
> juniper-nsp at puck.nether.net
> https://puck.nether.net/mailman/listinfo/juniper-nsp
>
> ------------------------------
>
> End of juniper-nsp Digest, Vol 132, Issue 17
> ********************************************
>
>