[cisco-voip] increasing Maximum Serving Count TFTP service parameter

Lelio Fulgenzi lelio at uoguelph.ca
Wed Mar 30 16:37:58 EDT 2011


ok. so i have to have that started before i do things and watch the delta i'm guessing.... 

--- 
Lelio Fulgenzi, B.A. 
Senior Analyst (CCS) * University of Guelph * Guelph, Ontario N1G 2W1 
(519) 824-4120 x56354 (519) 767-1060 FAX (JNHN) 
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 
Cooking with unix is easy. You just sed it and forget it. 
- LFJ (with apologies to Mr. Popeil) 


----- Original Message -----
From: "Ryan Ratliff" <rratliff at cisco.com> 
To: "Lelio Fulgenzi" <lelio at uoguelph.ca> 
Cc: "Wes Sisk" <wsisk at cisco.com>, cisco-voip at puck.nether.net 
Sent: Wednesday, March 30, 2011 4:31:59 PM 
Subject: Re: [cisco-voip] increasing Maximum Serving Count TFTP service parameter 

Windows RTMT counters are available in perfmon (performance monitor). Look for Cisco TFTP iirc. 



-Ryan 


On Mar 30, 2011, at 3:26 PM, Lelio Fulgenzi wrote: 


Thanks Wes. I was thinking about the BAT tool but didn't realize there was an actual Reset/Restart option. Even better - there's an option to reset phones based on a file! This is great. Today I was able to get all but 256 updated so it will be better to reset only those phones that need resetting. 

I'll have to check out the TFTP perfmon counter. We're using v4.1(3) - any hints where to find it? Our RTMT tool is not working with v4.1(3) so I'm not sure how we'll get to it. Problems after installing the RTMT tool for v7. :( 

Most of the phones in question are on our campus and those that are not are on a high speed, low latency link. (see below for ping from pub to two remote gateways) 

There wasn't anything else happening. TFTP server is dedicated. Not even DHCP any more! ;) 




C:\>ping 10.104.122.129 

Pinging 10.104.122.129 with 32 bytes of data: 

Reply from 10.104.122.129: bytes=32 time=19ms TTL=252 
Reply from 10.104.122.129: bytes=32 time=13ms TTL=252 
Reply from 10.104.122.129: bytes=32 time=13ms TTL=252 
Reply from 10.104.122.129: bytes=32 time=13ms TTL=252 

Ping statistics for 10.104.122.129: 
Packets: Sent = 4, Received = 4, Lost = 0 (0% loss), 
Approximate round trip times in milli-seconds: 
Minimum = 13ms, Maximum = 19ms, Average = 14ms 

C:\>ping 10.104.106.1 

Pinging 10.104.106.1 with 32 bytes of data: 

Reply from 10.104.106.1: bytes=32 time=8ms TTL=252 
Reply from 10.104.106.1: bytes=32 time=9ms TTL=252 
Reply from 10.104.106.1: bytes=32 time=9ms TTL=252 
Reply from 10.104.106.1: bytes=32 time=12ms TTL=252 

Ping statistics for 10.104.106.1: 
Packets: Sent = 4, Received = 4, Lost = 0 (0% loss), 
Approximate round trip times in milli-seconds: 
Minimum = 8ms, Maximum = 12ms, Average = 9ms 


--- 
Lelio Fulgenzi, B.A. 
Senior Analyst (CCS) * University of Guelph * Guelph, Ontario N1G 2W1 
(519) 824-4120 x56354 (519) 767-1060 FAX (JNHN) 
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 
Cooking with unix is easy. You just sed it and forget it. 
- LFJ (with apologies to Mr. Popeil) 


----- Original Message -----
From: "Wes Sisk" < wsisk at cisco.com > 
To: "Lelio Fulgenzi" < lelio at uoguelph.ca > 
Cc: cisco-voip at puck.nether.net 
Sent: Wednesday, March 30, 2011 10:51:25 AM 
Subject: Re: [cisco-voip] increasing Maximum Serving Count TFTP service parameter 

A few things come to mind - 
you can use BAT to reset phones at a slower rate in smaller groups. just tick the box to reset the phones. BAT changes are throttled so phones will have a better chance at success. 

There is a TFTP perfmon counter that indicates when serving count has been exceeded. If that incremented then increasing serving count may be beneficial. If that didn't increment then the problem lies elsewhere. 

I don't see a CM version indicated here. I also don't see indication of what other activities may have been going on when the reset was attempted. Activities like updating device pools or CM groups cause TFTP to rebuild all files. Rebuilding files can be slow. It is slowed further if this is pre-6.x where all database reads go to the publisher and the publisher is located across a WAN. Informix reads over WAN are particularly painful. Windows versions had a TFTP service parameter to "write TFTP files to disk" which further slowed TFTP rebuilds. TFTP requests while TFTP is rebuilding cause "processing allocation exceeded" (text may be different, memory is a bit fuzzy) which increments the same perfmon counter mentioned above. 

If the phones are over a WAN from the TFTP server this is also exacerbated. TFTP over wan is slow causing transfer to take longer which keeps each thread busy longer which causes more processing allocation exceeded. Best bet in this scenario is controlled reset of phones, see the BAT approach above. 

Digging even deeper TFTP transactions fail more frequently when there is a speed/duplex mismatch between the TFTP server and the connected switch. Ironically this too manifests more often when phones are over a WAN away from the TFTP server. 

If the TFTP server is not also running call processing then increasing thread count should be safe. 

Regards, 
Wes 

On 3/29/2011 5:02 PM, Lelio Fulgenzi wrote: 


I'm trying to upgrade about 4000 7940s and this morning's first attempt didn't pan out so well. 

After two resets, only 850 of them upgraded. 

I am resetting all phones from the device defaults page. I don't have any other way to reset b/c device pools contain other phone models. 

Any advantage to increasing the Maximum Serving Count TFTP service parameter? It's currently set to 1000, but it says I can increase this to 5000. 

We have advanced server running on our dedicated TFTP server. Properties shows Pentium III 1266MHz with 2GB RAM. 

thoughts? 



This parameter specifies the maximum number of client requests to accept and to serve files at a time. Specify a low value if you are serving files over a low bandwidth connection. You can set it to a higher number if you are serving small files over a large bandwidth connection and when CPU resources are available, such as when no other services run on the TFTP server. Use the default value if the TFTP service is run along with other Cisco CallManager services on the same server. Use the following suggested values for a dedicated TFTP server: 1500 for a single-processor system and 3000 for a dual-processor system. If the dual-processor system is running Windows 2000 Advanced Server, the serving count can be up to 5000. 
This is a required field. 
Default: 200. 
Minimum: 1. 
Maximum: 5000. 


--- 
Lelio Fulgenzi, B.A. 
Senior Analyst (CCS) * University of Guelph * Guelph, Ontario N1G 2W1 
(519) 824-4120 x56354 (519) 767-1060 FAX (JNHN) 
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 
Cooking with unix is easy. You just sed it and forget it. 
- LFJ (with apologies to Mr. Popeil) 


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