Slow Transfer using Fiber

Unanswered Question
Jul 22nd, 2009
User Badges:

I am having problems with my tranfer from a virtual server to clients. clients to server speed is exceptable. I am running Fiber from the virtual machine to the Catalyst 3560 port both set to gibit auto. see attachment for show run and show interface. I am thinking I am getting a bottleneck becuase everything else on my network is running 100 duplex. but the speeds I am getting coming out the virtual server is only like 30-50 mbs going in is 100 + mbs

  • 1
  • 2
  • 3
  • 4
  • 5
Overall Rating: 0 (0 ratings)
Marvin Rhoads Wed, 07/22/2009 - 12:26
User Badges:
  • Super Silver, 17500 points or more
  • Cisco Designated VIP,

    2017 Firewalling, Network Management, VPN

Your "show interface" command output seems to have gotten garbled in your attachment. It should read something like:

Switch# show interfaces gigabitethernet0/2

GigabitEthernet0/2 is down, line protocol is down

Hardware is Gigabit Ethernet, address is 0009.43a7.d085 (bia 0009.43a7.d085)

MTU 1500 bytes, BW 10000 Kbit, DLY 1000 usec,

reliability 255/255, txload 1/255, rxload 1/255

Encapsulation ARPA, loopback not set

Keepalive set (10 sec)

Auto-duplex, Auto-speed


A duplex mismatch is possible but unlikely with Gigabit Ethernet fiber interfaces. The duplex command is not supported on 3560 fiber interfaces. Can you set it to forced full-duplex on your server?

Given that it's a virtual server, it may be sharing network I/O with other server instances on the physical machine. Might they be preventing that one instance from achieving its potential? Can you isolate the operations and run a utility such a s ttcp to check the theoretical maximum? See the following link for tips on using ttcp:

Hope this helps.


This Discussion