One thing I would check for first is unicast flooding. It sounds like the backup router is flooding all traffic as it doesn't have any arp/mac tables created for traffic that comes ingress to it. Would be hard to pinpoint the issue unless you can provide some traffic flow stats.
Unicast flooding is a common problem with active/backup switching environments. If this is the case we can work on modifying the mac and arp timers to resolve it. Hope this helps Sent via BlackBerry by AT&T -----Original Message----- From: Alexandre Snarskii <[email protected]> Date: Sun, 14 Mar 2010 14:25:49 To: Juniper-NSP Mailing list<[email protected]> Subject: [j-nsp] mysterious microbursts ? Hi! During routine maintenance on my ex-3200 switches I found that some devices, connected with 100mbit/full-duplex observe minor packet loss. Well, there is nothing too unexpected, you can see it mostly every time when traffic enters switch using 1ge (2x1ge aggregate in my case) link and exits using 100mbit, switch ports just do not have enough buffer space to handle bursts well, but... That's where the strangeness begins: a) these 100mbit ports used to connect VoIP devices handling RTP traffic, so there should be no bursts at all. b) there are more than 30 such devices in my network, and I see that loss only on half of them - on that half that is connected to even-numbered switches, there are no packet loss on devices connected to odd-numbered ones. Logical topology is just "a vlan connected to a router (two routers in VRRP master/slave scenario)", physical is classic ring (some rings actually, each odd-numbered access switch connected to coresw1, even-numbered - to coresw2): router1 router2(backup, no traffic right now) | | coresw1 ================ coresw2 | | | | accsw1 -------- x ------ accsw2 link between core switches is 10ge, links core-access and access-access is 2x ge aggregated ethernet, access-access links are blocked by STP. Switches is ex3200-24t(core) and ex3200-48t(access), running 9.3R4.4. Well, these losses is about 0.1% and I can live with that, but I'd like to have any idea on why it happens only on half of devices, and I don't have one :( Any clue ? Example interface with errors: Physical interface: ge-0/0/26, Enabled, Physical link is Up Interface index: 165, SNMP ifIndex: 174, Generation: 168 Link-level type: Ethernet, MTU: 1514, Speed: 100mbps, Duplex: Full-Duplex, MAC-REWRITE Error: None, Loopback: Disabled, Source filtering: Disabled, Flow control: Enabled, Auto-negotiation: Disabled, Remote fault: Online Device flags : Present Running Interface flags: SNMP-Traps Internal: 0x0 Link flags : None CoS queues : 8 supported, 8 maximum usable queues Hold-times : Up 0 ms, Down 0 ms Current address: 00:19:e2:53:66:9a, Hardware address: 00:19:e2:53:66:9a Last flapped : 2010-03-05 04:36:34 PST (1w1d 22:21 ago) Statistics last cleared: 2010-03-11 06:44:54 PST (2d 20:13 ago) Traffic statistics: Input bytes : 88312256790 0 bps Output bytes : 88616684644 5984 bps Input packets: 443797702 0 pps Output packets: 412072442 10 pps IPv6 transit statistics: Input bytes : 0 Output bytes : 0 Input packets: 0 Output packets: 0 Input errors: Errors: 0, Drops: 0, Framing errors: 0, Runts: 0, Policed discards: 0, L3 incompletes: 0, L2 channel errors: 0, L2 mismatch timeouts: 0, FIFO errors: 0, Resource errors: 0 Output errors: Carrier transitions: 0, Errors: 0, Drops: 0, Collisions: 0, Aged packets: 0, FIFO errors: 0, HS link CRC errors: 0, MTU errors: 0, Resource errors: 0 Egress queues: 8 supported, 4 in use Queue counters: Queued packets Transmitted packets Dropped packets 0 best-effort 0 411934501 454642 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 1 assured-forw 0 0 0 5 expedited-fo 0 0 0 7 network-cont 0 137336 0 Active alarms : None Active defects : None MAC statistics: Receive Transmit Total octets 88312256790 88616684644 Total packets 443797702 412072442 Unicast packets 443796941 410096125 Broadcast packets 761 447035 Multicast packets 0 1529282 CRC/Align errors 0 0 FIFO errors 0 0 MAC control frames 0 0 MAC pause frames 0 0 Oversized frames 0 Jabber frames 0 Fragment frames 0 Code violations 0 Autonegotiation information: Negotiation status: Incomplete Packet Forwarding Engine configuration: Destination slot: 0 Direction : Output CoS transmit queue Bandwidth Buffer Priority Limit % bps % usec 0 best-effort 95 95000000 95 NA low none 7 network-control 5 5000000 5 NA low none _______________________________________________ juniper-nsp mailing list [email protected] https://puck.nether.net/mailman/listinfo/juniper-nsp _______________________________________________ juniper-nsp mailing list [email protected] https://puck.nether.net/mailman/listinfo/juniper-nsp
