09-10-2007 12:31 AM - edited 03-05-2019 06:22 PM
Good Morning to all of you,
I have a strange problem with our Cisco 2801 Router in a Intranet with 3Com 4200G Switch. The router is connected via F0/0 to the 3Com Switch and via F0/1 to a HP 5304XL. The transfer from F0/1 to F0/0 is fine. 90% network utilization. Transfer the other way provides only 10-20% performance. If I replace 3Com switch with HP I'll get 40-90%. And if I replace HP with a cheap Netgear switch, then I'll get the same as from F0/0 to F0/1, 90%.
Can anybody tell me something on this strange phenomenon? The Cisco IOS is 12.3 .There is only routing activated on the 2801.
thanx a lot.
Seb.
09-10-2007 03:19 AM
Hello Sebastian,
Not knowing the reason for your particular problem due to the lack of show outputs, the usual reason for performance issues in such an environment is a duplex mismatch.
Unfortunately real environments teach us that auto negotiation will not always succeed. Thus make sure both, the switch port and the router interface are configured to 100 mbps and duplex full.
Can you describe your findings with fixed speed and duplex settings? Do you see retransmissions? Pause frames?
Regards, Martin
09-10-2007 03:27 AM
Hi,
which outputs do you need?
sh int f0/0 + 0/1 shows that both interfaces are set up to 100 auto and duplex auto.
This works with HP and Netgear fine, both on auto mode. Only 3Com has problems with the router. We also set all ports (servers, switches, router) to 100M full. No change at all. Speed from the server (3Com) to server (HP) is still slow. The other way works fine. (90% of 100Mb)
09-10-2007 05:00 AM
Hi,
What happens, if you f.e attach the Netgear between the router and the 3Com switch? I just would like to know, whether is is an "interoperability issue" or the 3Com switch alone causing the issue.
Do you see retransmissions? Any error counters on any router interface or 3Com switch interface?
Regards, Martin
09-10-2007 07:13 AM
Hi,
srv1 -- 3com -- netgear -- cisco -- hp -- srv2
nothing changes
srv1 -- netgear -- cisco -- hp -- srv2
works fine from both sides
srv1 -- hp -- cisco -- hp -- srv2
works fine from srv2 --> srv1
but little bit slower the other way
srv1 -- 3com -- cisco -- hp -- srv2
the normal config!
works fine from srv2 --> srv1
but slow (10-20%) from srv2 --> srv1
09-11-2007 10:45 PM
Hi,
just to make sure I understand:
srv1 -- 3com -- netgear -- cisco -- hp -- srv2
nothing changes
This means "works fine from both sides" or "slow (10-20%)"?
Can you also provide show interface outputs from the router-3Com interface and the respective information from the 3Com for both the interfaces connecting to srv1 and the router?
Is it sure that the srv1 and respective 3Com port are both fixed speed and duplex? And are you seeing pause frames or dropped frames on any of the involved ports?
Regards, Martin
09-12-2007 05:21 AM
ok, let's check.
srv1 -- netgear -- cisco -- hp -- srv2
this works fine from both sides.
srv1 -- 3com -- cisco -- hp -- srv2
this only from srv2 --> srv1
the other way 10-20%
09-12-2007 05:25 AM
cisco2801#sh int f0/0
FastEthernet0/0 is up, line protocol is up
Hardware is Gt96k FE, address is 001a.a1f3.ee1a (bia 001a.a1f3.ee1a)
Description: $ETH-SW-LAUNCH$$INTF-INFO-FE 0$$FW_INSIDE$$ETH-LAN$
Internet address is 192.168.4.140/24
MTU 1500 bytes, BW 100000 Kbit, DLY 100 usec,
reliability 255/255, txload 1/255, rxload 2/255
Encapsulation ARPA, loopback not set
Keepalive set (10 sec)
Full-duplex, 100Mb/s, 100BaseTX/FX
ARP type: ARPA, ARP Timeout 04:00:00
Last input 00:00:00, output 00:00:00, output hang never
Last clearing of "show interface" counters never
Input queue: 1/75/0/0 (size/max/drops/flushes); Total output drops: 0
Queueing strategy: fifo
Output queue: 0/40 (size/max)
5 minute input rate 1090000 bits/sec, 180 packets/sec
5 minute output rate 155000 bits/sec, 142 packets/sec
12997102 packets input, 2828049833 bytes
Received 1371055 broadcasts, 0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
0 watchdog
0 input packets with dribble condition detected
12799024 packets output, 71310236 bytes, 0 underruns
0 output errors, 0 collisions, 3 interface resets
0 babbles, 0 late collision, 0 deferred
0 lost carrier, 0 no carrier
0 output buffer failures, 0 output buffers swapped out
this is the interface connected to 3Com Switch.
All speeds are set to "auto", as it is per default.
I also tried several combinations of fixed speeds and duplex, also with the servers.
Nothing changed.
I'll take a look at the 3Com now to provide you more infos.
09-12-2007 06:48 AM
the configuration of 3Com - Port to Cisco.
Port State Enable[Active] PVID 1
Flow Control Disable Link Type Access
MDI Auto Speed Auto[100]
Duplex Auto[Full] Max MAC Count No Limit
Jumbo Frame Enabled Port Isolate Disabled
Broadcast Suppression 3000(pps)
09-21-2007 01:10 AM
The problem is still valid.
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