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New Member

how to imrpove throughput-urgent

Our two offices in two different cities, they are connected to eachother through internet bandwidth. At both the places, each office cisco router is connected with their near by ISP. Now we creat a GRE Tunnel from ethernet to ethernet for all data transfer between our offices internal network. here is my configuration at one side, the same is at other side.

GEO-LAHORE#show inter ser 0/0

Serial0/0 is up, line protocol is up

Hardware is PowerQUICC Serial

Description: 256k radio link->COMSATS LHR

Internet address is 210.56.31.21/30

MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec,

reliability 255/255, txload 1/255, rxload 6/255

Encapsulation HDLC, loopback not set

Keepalive set (10 sec)

Last input 00:00:00, output 00:00:00, output hang never

Last clearing of "show interface" counters never

Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0

Queueing strategy: weighted fair

Output queue: 0/1000/64/0 (size/max total/threshold/drops)

Conversations 0/41/256 (active/max active/max total)

Reserved Conversations 0/0 (allocated/max allocated)

Available Bandwidth 1158 kilobits/sec

5 minute input rate 41000 bits/sec, 3 packets/sec

5 minute output rate 5000 bits/sec, 5 packets/sec

177019 packets input, 137075922 bytes, 0 no buffer

Received 6483 broadcasts, 0 runts, 0 giants, 0 throttles

1 input errors, 0 CRC, 1 frame, 0 overrun, 0 ignored, 0 abort

171449 packets output, 19617553 bytes, 0 underruns

0 output errors, 0 collisions, 1 interface resets

0 output buffer failures, 0 output buffers swapped out

0 carrier transitions

DCD=up DSR=up DTR=up RTS=up CTS=up

GEO-LAHORE#sho inter tunnel 1

Tunnel1 is up, line protocol is up

Hardware is Tunnel

Description: 210.56.0.133

Internet address is 10.254.2.2/16

MTU 1514 bytes, BW 9 Kbit, DLY 500000 usec,

reliability 255/255, txload 28/255, rxload 85/255

Encapsulation TUNNEL, loopback not set

Keepalive set (10 sec)

Tunnel source 210.56.20.137 (FastEthernet0/0), destination 210.56.3.33

Tunnel protocol/transport GRE/IP, key disabled, sequencing disabled

Tunnel TTL 255

Checksumming of packets disabled, fast tunneling enabled

Last input 00:00:02, output 00:00:01, output hang never

Last clearing of "show interface" counters never

Queueing strategy: fifo

Output queue 0/0, 32 drops; input queue 0/75, 0 drops

5 minute input rate 3000 bits/sec, 0 packets/sec

5 minute output rate 0 bits/sec, 0 packets/sec

20303 packets input, 7731177 bytes, 0 no buffer

Received 0 broadcasts, 0 runts, 0 giants, 0 throttles

0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort

23444 packets output, 3065630 bytes, 0 underruns

0 output errors, 0 collisions, 0 interface resets

0 output buffer failures, 0 output buffers swapped out

GEO-LAHORE#

I am using EIGRP as routing protocol.

I have 256 kbps bandwith at each site. While browsing internet I get throughput 20 to 25 KBites, but when I transfer files suing ftp at our internal network, browse some our internal web site that uses tunnel offcource, the throughput is only 2 to 4 KBites. Both the tarffics, internet and intenal are routed through internet 256 Kbps bandwith but why I am getting different throughput. How can I improve the throughput of my tunnel to 20 to 25 KBites like normal normal internet browsing.

Kindly Help me out.

4 REPLIES

Re: how to imrpove throughput-urgent

To help with this one it would help if you posted the configs and router models. Not enough to go on with this. Could be IPsec issue or gre/cef issue or anything else without more info.

Steve

New Member

Re: how to imrpove throughput-urgent

routera at both the places are Cisco 1751. No Ipsec is being used. No encryption protocol is used. tunnel is using GRE with our any encryption. please help.

Imran

Re: how to imrpove throughput-urgent

Again, without seeing the configs it is hard to troubleshoot this one. I have found various bugs about GRE and it causing traffic to be process switched and not fast switched or CEF. For example CSCdp20755 and CSCdu57390.

My advice again is post the config or search for bugs or call TAC.

Steve

New Member

Re: how to imrpove throughput-urgent

I don't think you will be able to acheive the same throughput on your GRE link as you do over straight internet browsing. There is a significant amount of overhead in maintaining the tunnel. Involved in that is latency at the router for the CPU encoding and decoding packets on both ends (less since you aren't encrypting) and reduced total packet payload. However, it does seem you should be getting alot more than 2 to 4KB.

You may want to look at the internet path between the two sites, or choosing a variety of internet websites to test throughput with. Perhaps you happen to have an optimal path to the server that is providing 20-25KB. Likewise, you may have a horribly inefficient path between your two locations. You may be assuming that there is a similarly performing path between the two tunnel locations in comparison to the path between your location and the internet site you're comparing it to.

If you want to guarantee that you have truly comparable performing internal and external paths, put up two identical web servers just outside and just inside the far end router. Then run your internet and intranet throughput tests within a close timeframe of each other from your location. You may even want to do a traceroute in between every stage of the test to ensure the route didn't change. This way you can guarantee the path, and have a more apples to apples comparison of internal and external throughput.

If you want to see how your link performs without the routers in the way at all, put a workstation just next to (and outside) your router and hit the test web server on the other end (which would also be outside of the router). This would enable you to see how the link performs without having any of your router in the way at all.

I wouldn't want to draw any conclusions without testing link performance between the two sites. The best way to do that is to remove as many of the elements in your control as you can.

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