My apologies for guessing about two sessions. I found through testing what
Marcelo confirmed, sessions 1 will allow a single call.
However, FOR THE LAB the number of software sessions per call is irrelevant
- configure it way higher than you think you'll need (10, 100, 500), UNLESS
the question tells you not to do that. If the question states "don't
configured DSPs that are not needed" this does not apply to software MTP,
as it doesn't use DSP resources. If you want to use a hardware MTP then
yes you should be worried about DSPs (I would recommend using a separate
transcoder and sticking with software MTP).
I wanted to also confirm my prior statement about codec pass-through and
understand when/why you should use it, so I did some further testing and
research today. The short answer is that FOR THE LAB it does not appear to
matter if you use codec pass-through, I got the same result for both with
and without pass-through. (Please note, I did yet not test complicated
scenarios such as a remote site phone calling to CCX which would use an MTP
for RSVP then a transcoder to g711 to talk to CCX.) Either way, the CUCM
region (g729) and location (bw unlimited, rsvp mandatory (with or without
video desired)) must still be set properly. Personally, I don't use
pass-through because it is one more variable if I need to troubleshoot and
it does not help me in the lab.
For the real world there are many compelling reasons to use codec
pass-through (for example cisco tells you to) including fax/modem calls and
sRTP, however those are not likely in the lab (I haven't seen them in any
IPExpert workbooks).
I expanded testing to see what effect codec pass through had on some other
setups (beyond what we expect to see in a lab). For example (test 4
below), if CUCM is set to use G711 and IOS MTP has g729r8 and codec
pass-through the call will setup using 96K and connect using 80K (sho ip
rsvp res). Thus, codec passthrough effectively IGNORES the codec setting
you have on the IOS MTP when the CUCM endpoints negotiate a codec. If the
CUCM endpoints do not negotiate, then the ios mtp codec setting will kick
in.
Keep reading if you're bored or curious :-)
-----------------------
Here's a "show sccp" with my config to look as sessions vs streams:
HQ-RTR#sho sccp
SCCP Admin State: UP
Gateway Local Interface: Loopback0
IPv4 Address: 10.10.110.1
Port Number: 2000
IP Precedence: 3
User Masked Codec list: None
Call Manager: 192.168.0.21, Port Number: 2000
Priority: N/A, Version: 5.0.1, Identifier: 2
Trustpoint: N/A
Call Manager: 192.168.0.101, Port Number: 2000
Priority: N/A, Version: 5.0.1, Identifier: 1
Trustpoint: N/A
MTP Oper State: ACTIVE - Cause Code: NONE
Active Call Manager: 192.168.0.101, Port Number: 2000
TCP Link Status: CONNECTED, Profile Identifier: 2
Reported Max Streams: 1000, Reported Max OOS Streams: 0 <<<
max STREAMS 1000 (2 streams per session configured (500), which does
indicate each session is one call with two "streams")
Supported Codec: g729r8, Maximum Packetization Period: 60
Supported Codec: rfc2833 dtmf, Maximum Packetization Period: 30
Supported Codec: rfc2833 pass-thru, Maximum Packetization Period: 30
Supported Codec: inband-dtmf to rfc2833 conversion, Maximum Packetization
Period: 30
RSVP : ENABLED
dspfarm profile 2 mtp
codec g729r8
rsvp
maximum sessions software 500
associate application SCCP
!
The output above max STREAMS 1000 while I configured 500 sessions - this
does indicate each session is one end-to-end call with two "streams," one
for each side of the mtp.
See attached (in a follow up email) detailed debugs of 5 test scenarios
(rsvp bandwidth was increased to allow multiple/g711 calls)
*First two test scenarios are relevant to the lab (with and without
pass-through RSVP works as expected)*
*1: region set g711, location set unlimited bw and rsvp mandatory, ios mtp
set g729*
-RESULT (as expected): rsvp uses *40k during setup, 24K when call
connects*
-note: "show sccp conn" shows codec as "G729," phones also show G729
in use
*2: same as test 1 but adding ios mtp "codec pass-through"*
-RESULT (as expected): rsvp uses *40k during setup, 24K when call
connects*
-note: "show sccp conn" shows codec as "pass-th," phones show G729 in
use
*Next two tests show codec pass-through ignores the codec set in IOS MTP*
*3: region set g711, location set unlimited bw and rsvp mandatory, ios mtp *
*no codec set** and pass-through on*
-RESULT (as expected): rsvp uses *96k during setup, 80K when call
connects*
-note: "show sccp conn" shows codec as "pass-th," phones show G711 in
use
*4: region set g711, location set unlimited bw and rsvp mandatory, ios mtp *
*set g729** and pass-through on*
-RESULT: *rsvp uses 96k during setup, 80K when call connects* (ios mtp
codec setting ignored because both phones negotiate g711)
-note: "show sccp conn" shows codec as "pass-th," phones show G711 in
use
*Last test shows how without codec pass-through the codec set in IOS MTP
will be used (at least in connected state)*
*5: region set g711, location set unlimited bw and rsvp mandatory, ios mtp set
g729*
-RESULT: rsvp uses *96k during setup*, *24K when call connects* (ios
mtp codec setting used when SCCP phone answers)
-note: "show sccp conn" shows codec as "pass-th," phones show G729 in
use
-note2: while the end result is g729 used, if rsvp bw was set to 64K
to allow 2 calls this call would fail because the call setup was trying to
use 96K which exceeded the rsvp bw.
Hope this helps...
-Justin
(attachments will be sent separately in case that email gets quarantined)
On Sat, Aug 17, 2013 at 8:39 AM, Marcelo Augusto <maugusto...@gmail.com>wrote:
> "max session software 1" will work with one call.
>
> is not correct the information about two session will be used in a pre
> call.
>
>
>
> On Sat, Aug 17, 2013 at 2:42 AM, IE Target <myfrnd...@gmail.com> wrote:
>
>>
>> That is something even i am not clear with
>>
>> One call = two call leg
>>
>> Practically if we configure
>> maximum session software 1
>>
>> the call works?
>>
>> some where i read that two sessions will be used pre call ??
>>
>> Any comments
>>
>>
>>
>>
>>
>>
>> _______________________________________________
>> For more information regarding industry leading CCIE Lab training, please
>> visit www.ipexpert.com
>>
>> Are you a CCNP or CCIE and looking for a job? Check out
>> www.PlatinumPlacement.com
>>
>
>
>
> --
> .:.::Marcelo Augusto::.:.
> MSN: harkonmose...@hotmail.com
> SKYPE: harkonmoseley
>
> _______________________________________________
> For more information regarding industry leading CCIE Lab training, please
> visit www.ipexpert.com
>
> Are you a CCNP or CCIE and looking for a job? Check out
> www.PlatinumPlacement.com
>
_______________________________________________
For more information regarding industry leading CCIE Lab training, please visit
www.ipexpert.com
Are you a CCNP or CCIE and looking for a job? Check out
www.PlatinumPlacement.com
