routers

[hayesp]

Hi,

Can anyone help me out. We are running an inhouse application that runs over citrix and a 512K leased line. The thing is that the application is now running really slowly. We are rebuilding the citrix server at present but I just thought that someone might be able to tell me if it could be an issue with the router itself, which is a 1600.

Thanks in advance.

Paul

 

[tschouten]

The better question is how many users are conecting to your Citrix server? How much bandwidth is each user on average consuming? Total the average multiple bandwidth consumption, and compare to available bandwidth. This could be part of your problem too many calls an a small pipe.

 

[sobak]

Does the application and data reside physically on the Citrix box or does it need to go over the router for some particular reason? If both application and data reside physically on the Citrix box then I don't believe it would be the router causing the problem. One test you could do is sign into the Citrix box directly and attempt to run the application if it's slow there then it's the box. Remember the only thing that passes to the Citrix client are screen shots. All data and processing is done on the Citrix Server.

david e
*end users are just like computers, some you can work with...others just need a simple reBOOTing to fix their problems.*

 

[sobak]

Tschouten good catch, overlooked that one...



david e
*end users are just like computers, some you can work with...others just need a simple reBOOTing to fix their problems.*

 

[hayesp]

There are only about 25 concurrent users at any one time. The application and data aren't on the citrix server but on a server on the same LAN. We have tried the program locally and it seems to work fine, it is just on the remote site that it seems to be slow. At the moment we are rebuilding the citrix server with the hope that this will have been the problem. Just one more thing, would anyone know if the 1600 router is fine for a 512K line, or should the router be upgraded?

 

[tschouten]

Yes the 1600 should be fine, but with 25 concurrent users you could be running out of available bandwidth. Depending on conditions. By users, I also mean are there users accessing the 512 pipe localy for email, www, etc.?

Add these into it and you could just have an overwhelmed pipe. Think about it for a second, let's say you have the 25 users on, each user is pulling 1.32kb a peice. That alone is 33kb per second. Which roughly is 16 percent of your pipe. While granted this doesn't seem like a lot start adding actuall usage of the pipe. You may be suprised to find you don't have aenough pipe for all the traffic.

Not saying it couldn't be the Citrix box itself. However, if local people pull from it fine I would be more concerned with how much bandwidth I have available. What do I have running on the main router, are there access-lists, rate-limiting, gre tunnels, encryption of any kind? All these things can contribute to time processing information.

 

[hayesp]

Hi Tschouten/Sobak, thanks for the help. We have an external company monitoring the bandwidth on the network and the only time that it actually gets close to 100% is at logon time in the morning. There is web access and e-mail over the same line but people are very restricted in these. Could you tell me how I would work out what bandwidth each user is using? The only other application that is running through Citrix over the same line is an accounts package and there is no problem at all with that one.

 

[tschouten]

Hmmm, they say you only hit high traffic in the morning during login. Makes sense, how many nic's do you have the Citrix box? I myself would suggest to gigabit Nic's and load-balance them, could just be too many calls are goinig to the box itself.

Maybe you should try the Citrix forum, I'm not very well versed in Citrix. I know it, I know slightly how it works. But troubleshooting problems with it, I don't know.

However, my first response would be to use a network analyzer in both locations. See if I can notice severe differrnces, or problems.

 

[WesF]

We are having a nearly identical problem. We were hitting our bandwidth limit (256K over partial T1) so we used our available channels to upgrade to 512K last night....still have the problem despite bandwidth reports only show us hitting about 30-40%. Our problem is this:

We only have one regular daytime user that stays connected to Citrix all day. He is on a fast cable connection. Citrix is extrememly slow. If he connects via our 19200 dial-up it is fast, but that dials directly into our LAN via RAS bypassing our router and firewall. I use cable at home, but have only seen the problem once for me. However, I typically only connect at night when the network traffic is way down.

We also have a Cisco 1601 router with the ethernet port (can only use 10MB/Half Duplex in 1600 series) connected to our firewall appliance, which connects to our LAN switch at 100MB/Full Duplex. I'm wondering if the half duplex on that port is causing havoc w/ Citrix when many other users are connected to e-mail and the Internet during the day.

 

[hayesp]

We never really found out what the issue was, we rebuilt the server and it did help but every now and then it goes extremely slowly. We ran a sniffer on the network and found that in a short period of time a desktop sent over 5mb to one of the citrix servers. We are now trying to work out why this happened. We are however going to up the line to 1mb, if I find out why this is happening I will post it and hope that it gives you some help.
Regards,
Paul

 

[cluey]

I think you will find that your problem is not bandwidth related. I would say that the cisco 1600 is pretty entry level. I would check cpu and memory stats on the router and see if it is over worked. We have many clients running a 512k/512k link with 20 plus citrix clients & have no problems with this bandwidth.

 

[hayesp]

Hi Cluey,
I had our network management company check out the cpu usage and memory of the router and they say that it is fine, not maxing out at all. I will continue trying things.
Regards,
Paul

 

[baddos]

Please post "show interface serial 0" and "show interface ethernet 0" taken during the "slow times".

 

[WesF]

Here is show interface from the last 5 days. "Slow Times" according to the user are pretty much all day. I have no way to confirm since I am on site during the day.

Ethernet0 is up, line protocol is up
Hardware is QUICC Ethernet, address is 0010.7bdf.4383 (bia 0010.7bdf.4383)
Internet address is X
MTU 1500 bytes, BW 10000 Kbit, DLY 1000 usec, rely 255/255, load 1/255
Encapsulation ARPA, loopback not set, keepalive set (10 sec)
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 4d22h
Queueing strategy: fifo
Output queue 0/40, 0 drops; input queue 0/75, 0 drops
5 minute input rate 9000 bits/sec, 10 packets/sec
5 minute output rate 38000 bits/sec, 11 packets/sec
2427289 packets input, 343573756 bytes, 0 no buffer
Received 10 broadcasts, 0 runts, 2 giants
4 input errors, 0 CRC, 2 frame, 0 overrun, 0 ignored, 0 abort
0 input packets with dribble condition detected
2877202 packets output, 1991999193 bytes, 0 underruns
0 output errors, 7369 collisions, 0 interface resets
0 babbles, 0 late collision, 10474 deferred
0 lost carrier, 0 no carrier
0 output buffer failures, 0 output buffers swapped out
0 output buffer failures, 0 output buffers swapped out


Serial0 is up, line protocol is up
Hardware is QUICC Serial
Internet address is X
MTU 1500 bytes, BW 512 Kbit, DLY 20000 usec, rely 255/255, load 3/255
Encapsulation HDLC, loopback not set, keepalive set (10 sec)
Last input 00:00:02, output 00:00:00, output hang never
Last clearing of "show interface" counters 4d22h
Input queue: 0/75/0 (size/max/drops); Total output drops: 37
Queueing strategy: weighted fair
Output queue: 0/64/37 (size/threshold/drops)
Conversations 0/66 (active/max active)
Reserved Conversations 0/0 (allocated/max allocated)
5 minute input rate 28000 bits/sec, 5 packets/sec
5 minute output rate 8000 bits/sec, 6 packets/sec
2892137 packets input, 1965216051 bytes, 8 no buffer
Received 50418 broadcasts, 0 runts, 0 giants
8 input errors, 8 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
2482761 packets output, 322713194 bytes, 0 underruns
0 output errors, 0 collisions, 0 interface resets
0 output buffer failures, 0 output buffers swapped out
0 carrier transitions
DCD=up DSR=up DTR=up RTS=up CTS=up


Also, here is info from the show controller command for Ethernet0 since it has many collisions:

0 missed datagrams, 0 overruns
0 transmitter underruns, 0 excessive collisions
1595 single collisions, 5794 multiple collisions
0 dma memory errors, 0 CRC errors

2 alignment errors, 0 runts, 2 giants
QUICC SCC specific errors:
0 buffer errors, 0 overflow errors
0 input aborts on late collisions
0 heartbeat failures, 0 cumulative deferred
4067 throttles, 4067 enables

 

[Cluebird]

You may consider implementing QoS on the serial links for the Citrix traffic so you can give it preferred treatment during congestion. You're using WFQ so consider CBWFQ to help.

 

[baddos]

Your router looks under utilized during these captures. How is the memory and cpu on it during these times?

Also... When the remote sites are having a slow citrix connection, try opening it up over your local LAN. If it's slow for your on your LAN, then it might be the citrix server. If it's fast for you on your LAN, but slow on the WAN then it is probably something in your network.

 

[WesF]

HayesP....do you have a firewall in between the router and the Citrix Server by any chance?

 

[WesF]

baddos...

Typically CPU is something like this:

CPU utilization for five seconds: 8%/7%; one minute: 16%; five minutes: 16%

Memory:

Head Total(b) Used(b) Free(b) Lowest(b) Largest(b)
Processor 203E35C 1318052 591128 726924 704556 710144
I/O 2180000 524288 196620 327668 254788 327668


Haven't noticed it being slow on the LAN at all, but it will bypass the firewall (Symantec Gateway Security Appliance) and router if on the LAN. The slowdown seems to only happen during peak network activity time though because at night I can connect with virtually no latency at all. I have already tweaked the Citrix rule in the firewall to speed it up...turned off application data scanning and normal logging for that rule.

 

[DaShard]

Buy a couple of new drives - 1 for each server. Put your Swap File and Print Spooler on to these dedicated drives on both Citrix and your File Server... That'll help tons...

 

[hayesp]

Hi WesF,

I don't have a firewall between these two routers as they are connected by leased line, however I do have a pix firewall connected to another router if that might be anything to do with it.

Regards,

Paul