Further info following response:
Failures get progressively worse pinging from a switch as packet size increases, 10/10 from a PC at any size Traffic levels are low in general, path from the ping source 2950 below is Gb to core>>> Gb to other core >>>Gb to distrib 3550>>> 100Mb to 2nd distrib 3550 >>> 100Mb suspect interface to test 2940 >From the ping source to the 3550 with the failed interface 16K packets are fine just not acros the last faulty interface to the Test 2940. Voice VLAN: none (Inactive) Appliance trust: none Name: Fa0/3 Switchport: Enabled Administrative Mode: dynamic desirable Operational Mode: trunk Administrative Trunking Encapsulation: dot1q Operational Trunking Encapsulation: dot1q Negotiation of Trunking: On Access Mode VLAN: 1 (default) Trunking Native Mode VLAN: 1 (default) Administrative private-vlan host-association: none Administrative private-vlan mapping: none Operational private-vlan: none Trunking VLANs Enabled: ALL Pruning VLANs Enabled: 2-1001 FastEthernet0/3 is up, line protocol is up Hardware is Fast Ethernet, address is 0009.xxxx.xxxx (bia 0009.xxxx.xxxx) Description: faulty MTU 1500 bytes, BW 100000 Kbit, DLY 100 usec, reliability 255/255, txload 1/255, rxload 1/255 Encapsulation ARPA, loopback not set Keepalive set (10 sec) Full-duplex, 100Mb/s input flow-control is off, output flow-control is off ARP type: ARPA, ARP Timeout 04:00:00 Last input 00:00:01, output 00:00:00, output hang never Last clearing of "show interface" counters 4d19h Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0 Queueing strategy: fifo Output queue :0/40 (size/max) 5 minute input rate 0 bits/sec, 0 packets/sec 5 minute output rate 0 bits/sec, 0 packets/sec 303603 packets input, 197232924 bytes, 0 no buffer Received 90320 broadcasts, 0 runts, 0 giants, 0 throttles 0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored 0 watchdog, 90288 multicast, 0 pause input 0 input packets with dribble condition detected 11901675 packets output, 1954047601 bytes, 0 underruns 0 output errors, 0 collisions, 0 interface resets 0 babbles, 0 late collision, 0 deferred 0 lost carrier, 0 no carrier, 0 PAUSE output 0 output buffer failures, 0 output buffers swapped out >From a win2K PC several hops away @ 16K: Reply from xx.xx.xx.xx: bytes=16000 time=78ms TTL=253 Reply from xx.xx.xx.xx: bytes=16000 time=76ms TTL=253 Reply from xx.xx.xx.xx: bytes=16000 time=77ms TTL=253 Reply from xx.xx.xx.xx: bytes=16000 time=77ms TTL=253 Reply from xx.xx.xx.xx: bytes=16000 time=76ms TTL=253 Ping statistics for xx.xx.xx.xx: Packets: Sent = 265, Received = 265, Lost = 0 (0% loss), Approximate round trip times in milli-seconds: Minimum = 76ms, Maximum = 81ms, Average = 76ms Control-C >From a 2950c several hops away: Sending 5, 100-byte ICMP Echos to xx.xx.xx.xx, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 4/4/4 ms Sending 5, 1000-byte ICMP Echos to xx.xx.xx.xx, timeout is 2 seconds: .!!.. Success rate is 40 percent (2/5), round-trip min/avg/max = 4/6/8 ms Sending 5, 2000-byte ICMP Echos to xx.xx.xx.xx, timeout is 2 seconds: ..!!! Success rate is 60 percent (3/5), round-trip min/avg/max = 12/12/12 ms Sending 5, 2000-byte ICMP Echos to xx.xx.xx.xx, timeout is 2 seconds: ....! Success rate is 20 percent (1/5), round-trip min/avg/max = 12/12/12 ms >Hi Kevin, > >Do the switches show high cpu or high throughput on those ports? If you >post the interface stats (e.g. show int switching, sh int, sh vlan) >perhaps it will help. >Are the two limits exactly 500 & 1000? I wasn't clear from your email if >this was the case or if you were giving an approx range. Is there a very >clear cut off after 1000 bytes, with no replies at all after that? >If the switch IP and PC were in the same vlan then the only differences >I can think of are that the extended ping may be sending at a faster >rate than a windows ping; the frame size is different if you enter 1000 >for each (the frame sent by windows would be 28 bytes larger); and the >switch may perhaps(?) drop or rate limit locally generated/destined icmp >before cef switched transit traffic if it is under heavy load. ICMP is >not normally considered high priority traffic. >What kind of traffic would you expect on the network, much multicasts or >broadcasts for instance? >Paul. ********************************************************************** This transmission is confidential and must not be used or disclosed by anyone other than the intended recipient. Neither Corus Group Limited nor any of its subsidiaries can accept any responsibility for any use or misuse of the transmission by anyone. 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