How many software MTP sessions ISR G2 Router can support?

[wclee1004]

I found that ISR G1 can support up to 1,000 individual streams(sessions), couldn't find ISR G2's maximum# of stream.

Anybody has the number?

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Router  configurations permit up to 1,000 individual streams, which support 500  transcoded sessions. This number of G.711 streams generates 10 Mbytes  of traffic. The Cisco ISR G2s and ASR routers can support significantly  higher numbers than this.

[Manish Gogna]

Hi,

There are no Official tools available for IOS software MTP capacity calculation, except the Voice Gateways 'DSP Calculator' tool on cisco.com.  However, this tool does not work for IOS SW MTP as they do not use DSPs.

Newer type of platforms like the 29xx and 39xx came to support up to 10000 IOS software  MTP sessions. As a matter of fact the following bug states that we can have more than one profile set it up with the maximum number of sessions CSCsq05099    Remove the upper limit on the MTP as it varies by platform

http://tools.cisco.com/Support/BugToolKit/search/getBugDetails.do?method=fetchBugDetails&bugId=CSCsq05099

However,  Having having 10000 sessions for IOS MTPs will result in CPU issues. The CPU will likely cut you off long before you get to 10000 sessions.

As per an internal tool to calculate the impact of software mtp sessions on CPU

>> 798 software MTP sessions will result in the CPU going over 99.9%, and this percentage is without considering other functions that the Router can perform like the ones you see in the image.

>> The suggested value is 440 sessions when the Router acts only as a SW MTP. This will result in 55% of the Router CPU.

>>  If the Router is acting as CUBE and SW MTP the suggested value is 220 sessions. This will result in 27.5% of the Router CPU

Others are welcome to add their inputs.

HTH

Manish

[wclee1004]

Thank you Manish,

We are thinking about implementing shared SW MTP on ASR1004.

Can we access SW MTP calculation tool to check how many concurrent sessions we can have?

If that is internal tool, can you calculate the number of sessions based on the spec below?

cisco ASR1004 (RP2) processor with 1596852K/6147K bytes of memory.

10 Gigabit Ethernet interfaces

32768K bytes of non-volatile configuration memory.

8388608K bytes of physical memory.

1925119K bytes of eUSB flash at bootflash:.

78085207K bytes of SATA hard disk at harddisk:.

[Manish Gogna]

Hi,

The tool provides details about impact of mtp sessions on CPU usage, it does not provide details of the max sessions configurable on a router. The only thing that you can try on this router is to create an MTP dspfarm profile and do a question mark after max sessions command.

Manish

[wclee1004]

That is exactly what I want to know. (the impact of SW MTP sessions on CPU use)

We can set 20,000 sessions on our ASR as below.

CUBE01-LONDUK(config-dspfarm-profile)#maximum sessions software ?

<1-20000>  Number of sessions assigned to this profile

But, I would like to know the actual session# our ASR can support without performace impact.

(cisco ASR1004 (RP2) processor with 1596852K/6147K bytes of memory)

And our ASR is running on CUBE-SP mode, not Enterprise.

Thank you,

Woocheol

[Manish Gogna · Accepted solution]

Hi,

To get an official confirmation i would recommend opening a case with the PDI Helpdesk.

http://www.cisco.com/go/pdihelpdesk

I do have some tentative data about the 3900 series routers. The number of Software MTP session that will be equivalent to 50% of the CPU usage:

3945 Integrated Services Router   (Software MTP sessions: 675 sessions)

3945E Integrated Services Router  (Software MTP sessions: 1680 sessions)

3925 Integrated Services Router   (Software MTP sessions: 630 session)

3925E Integrated Services Router  (Software MTP sessions: 1420 sessions)

But for a large scale deployment i suggest getting an official word.

HTH

Manish

[wclee1004]

I'm opening PDI case.

Thank you Manish,

Woocheol

[Aman Soi]

Hi Manish,

Thanks for sharing useful info[+5].

I was trying to access the bug but says does not exist.

regds,

aman

[Manish Gogna]

Hi Aman,

Please try the following link

https://tools.cisco.com/bugsearch/bug/CSCsq05099

Here is what it says.

Remove the upper limit on the MTP as it varies by platform

CSCsq05099

Description

Symptoms: User can only configure a maximum of 500 SWMTP sessions per profile.
Conditions: This symptom is observed when using SWMTP.
Workaround: Configure multiple SWMTP profiles.

Manish

[Manish Gogna]

Final Answer:

Maximum limit of software MTP on ASR1004 with RP2 is 5000.

The above figure is based on G711 codec and assumes that the Router won't be doing anything else other than software MTP functions, keeping CPU average below 75%.

Manish

[wclee1004]

Thank you Manish,

I understand CUBE enterprise edition will work as you guided(5000 SW MTP sessions with 75% CPU load)

But, our ASR1004 is CUBE SP edition. Will it work in same way?

Thank you,

Woocheol.

[Manish Gogna]

From the datasheets of the two routers the hardware and more importantly the processors are similar so ideally there shouldn't be a difference between the two. Additionally, 5000 is a theoretical limit and you would agree that in a real worls scenario no one would try to even come close to that limit.

Manish

[wclee1004]

Thanks Manish,

3945E can be a best candidate for us.

By the wayt, do you have same # of session information for 2851 and 38xx router by chance?

[Manish Gogna]

Hi,

I'll check and get back.

Manish

[Manish Gogna · Accepted solution]

Hi,

I found this information for you in a TAC case. However, as i mentioned earlier as well before you go for final deployment its always good to check with the Cisco PDI team for a confirmation of exact numbers.

Below you will find the number of Software MTP session that will be equivalent to 50% of the CPU usage:

Cisco 3900 Series

.             3945 Integrated Services Router   (Software MTP sessions: 675 sessions)

.             3945E Integrated Services Router  (Software MTP sessions: 1680 sessions)

.             3925 Integrated Services Router   (Software MTP sessions: 630 sessions)

.             3925E Integrated Services Router  (Software MTP sessions: 1420 sessions)

Cisco 2900 Series

.             2951 Integrated Services Router   (Software MTP sessions: 565 sessions)

.             2921 Integrated Services Router   (Software MTP sessions: 400 sessions)

.             2911 Integrated Services Router   (Software MTP sessions: 335 sessions)

.             2901 Integrated Services Router   (Software MTP sessions: 300 sessions)

Cisco 3800 Series

.             3845 Integrated Services Router   (Software MTP sessions: 390 sessions)

.             3825 Integrated Services Router   (Software MTP sessions: 320 sessions)

Cisco 2800 Series

.             2851 Integrated Services Router   (Software MTP sessions: 175 sessions)

.             2821 Integrated Services Router   (Software MTP sessions: 160 sessions)

.             2811 Integrated Services Router   (Software MTP sessions: 90 sessions)

.             2801 Integrated Services Router   (Software MTP sessions: 95 sessions)

HTH

Manish