Date: Tue, 28 Aug 2001 01:05:32 -0400 From: Mike Tancsa <mike@sentex.net> To: freebsd-net@freebsd.org Subject: Runt frames = broken VLAN ? Message-ID: <5.1.0.14.0.20010828010515.0221d380@192.168.0.12>
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Can anyone tell me why the VLAN code might be causing my switches (ciscos)
to see a lot of runt frames when the interface is in 802.1q trunking mode ?
The same nic in the same port in regular ethernet mode does not cause this.
e.g.
FastEthernet0/20 is up, line protocol is up
Hardware is Fast Ethernet, address is 0030.9410.9696 (bia 0030.9410.9696)
Description: test trunking ports
MTU 1500 bytes, BW 100000 Kbit, DLY 100 usec, rely 255/255, load 1/255
Encapsulation ARPA, loopback not set, keepalive not set
Full-duplex, 100Mb/s, 100BaseTX/FX
ARP type: ARPA, ARP Timeout 04:00:00
Last input never, output 00:00:01, output hang never
Last clearing of "show interface" counters 02:10:40
Queueing strategy: fifo
Output queue 0/40, 0 drops; input queue 0/75, 0 drops
5 minute input rate 0 bits/sec, 0 packets/sec
5 minute output rate 1000 bits/sec, 3 packets/sec
11534 packets input, 2204339 bytes, 0 no buffer
Received 0 broadcasts, 23 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
0 watchdog, 0 multicast
0 input packets with dribble condition detected
23960 packets output, 18559944 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 output buffer failures, 0 output buffers swapped out
ping -c 3 -s 10 host-on-the-other-side
will increment the runt count by 3 each time.
The cisco looks like
interface FastEthernet0/20
speed 100
duplex full
switchport trunk encapsulation dot1q
switchport trunk allowed vlan 1,105-125,1002-1005
switchport mode trunk
!
The nic looks like
fxp1: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
inet 10.255.255.253 netmask 0xfffffffc broadcast 10.255.255.255
inet6 fe80::201:80ff:fe05:9356%fxp1 prefixlen 64 scopeid 0x3
ether 00:01:80:05:93:56
media: Ethernet 100baseTX <full-duplex>
status: active
The config statement looks like
ifconfig vlan0 1.2.3.1 netmask 255.255.255.252 vlan 105 vlandev fxp1 mtu
1500 up
If the other side is 1.2.3.2
ping -c 3 -s 10 1.2.3.2
from anywhere on the net, will cause the runt frames to increase by 3. i.e.
with each small ping packet, I get a runt frame.
According to Cisco's documentation, runt frames are a sign of collisions
(this is full duplex end to end) in a non switched network, or a sign of
broken software ie. the driver. Does anyone know what might be going on ?
---Mike
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