08-01-2006 09:53 PM
I have a question about NFAS groups and RLM groups.
We run a PGW (9.4.1) in nailed mode.
We connect via SS7 to Telco_X through 2 Signaling Points (DPC's), via a single AS5400.
Consider an E1 from each SP, carrying the same type of type traffic (determined by digit string).
All traffic prefixed with 123 is to terminate via these E1's.
I think I have 2 options for the AS5400 configuration, diagrams outlining each option are attached...
Option 1
trunk group Service_A
!
controller E1 6/0
pri-group timeslots 1-31 nfas_d primary nfas_int 0 nfas_group 0 rlm-group 0
description Switch A - cic's 1 <->31
!
controller E1 6/1
pri-group timeslots 1-31 nfas_d none nfas_int 1 nfas_group 0
description Switch B - cic's 1 <->31
!
interface Dchannel6/0
trunk-group Service_A
!
rlm group 0
server PGW-A
link address x.x.x.x source GigabitEthernet0/0.1 weight 2
link address x.x.x.x source GigabitEthernet0/0.1 weight 1
!
dial-peer voice123 pots
trunkgroup Service_A
destination-pattern123.%
Will the above approach work, or will I need a separate RLM/NFAS group for each switch (DPC), I connect to... as shown below
i.e; Option 2
trunk group Service_A
!
controller E1 6/0
pri-group timeslots 1-31 nfas_d primary nfas_int 0 nfas_group 0 rlm-group 0
description Switch A - cic's 1 <->31
!
controller E1 6/1
pri-group timeslots 1-31 nfas_d primary nfas_int 1 nfas_group 1 rlm-group 1
description Switch B - cic's 1 <->31
!
interface Dchannel6/0
trunk-group Service_A
!
interface Dchannel6/1
trunk-group Service_A
!
rlm group 0
server PGW-A
link address x.x.x.x source GigabitEthernet0/0.1 weight 2
link address x.x.x.x source GigabitEthernet0/0.1 weight 1
!
rlm group 1
protocol rlm port 3002
server PGW-A
link address x.x.x.x source GigabitEthernet0/0.1 weight 2
link address x.x.x.x source GigabitEthernet0/0.1 weight 1
!
dial-peer voice123 pots
trunkgroup Service_A
destination-pattern123.%
I am figuring that the 1st option will work, as the PGW can determine the relationship between the source and destination signaling services and span/timeslots through the nailed trunk provisioning (trunk.dat file)
If I then add 2 more E1's to each switch, and then route calls prefixed with 123 to cic's 1-31, calls with 246 to cics 33-63, and calls with 357 to cics 65-95, I will require a separate RLM/NFAS group for each terminating prefix.
If the second option above is correct, I am going to need 6 RLM groups on the GW. The PGW/GW spec's say that 8 are supported, however, I have read that in practice, you really dont want to go past 5. I believe this was due to an IOS limitation.
Any pointers as to whether "option 1" will fly are greatly appreciated.
08-03-2006 11:21 AM
Option one will not work. Only the first E1 will work. If you have only 1 RLM group you only have 1 D-Channel between the PGW and that gateway.
Hope this helps answer your question.
08-03-2006 01:23 PM
Thanks,
It looks like I am going to need 6, possibly 7 RLM Groups on the GW.
Can you tell me whether the operational limit of 5 RLM's per GW still exists. I have this info from a training course I did 3 years ago, so it may now not be a problem. It is in the documentation I have from the "Building Cisco SS7 Interconnect & VOIP Networks for Voice and Dial Traffic" course.
08-04-2006 05:32 PM
If you are running a 9.X release of PGW you can run 8 RLM groups. Again you only need one RLM group per DPC that is connecting to this gateway. If you need 7 as you say that mean that you have 7 DPCs connecting their E1/T1s to the same gateway.
Andreas
08-06-2006 08:34 PM
I may be missing something very basic here, but I am still struggling to see how I can route various digit strings at specific E1's.
eg;
service_a
dest-patt 123.......goes to cic's 01-31 at both SSP's
service_b
dest-patt 246.......goes to cic's 33-63 at both SSP's
service_c
dest-patt 357.......goes to cic's 65-95 at both SSP's
In the past I have created a trunk group for each service type, and then a separate RLM/NFAS group for each, and then associated the dchannel created for each nfas group with the required trunk-group. The pots dial-peer then matches the specific digit strings to the trunk-group.
How can I achieve the same result with only 1 RLM group per DPC?
08-03-2006 11:26 AM
Sorry, I forgot to respond to the second part of your question.
If you add more E1s to the same switch (SSP/DPC) then you have no need of adding additional RLM groups as you already have the D-channel for those 2 SSPs. If however you plan on going to additional SSPs and want their E1s to terminate on this same gateway only then would you need to add addition RLM groups.
Regards
Andreas
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