Outbound Dial-peer selection example from Global Knowledge

[Difan Zhao]

Hi experts,

I am taking some global knowledge voip training (self-paced). She is talking about how the outbound dial-peer is selected. She said and I confirmed on google that, destination-pattern is the only rule used for matching. However please take a look at the screen shot picture. Does it make sense to you? If they do, why?

Also the wildcard "." in the destination-pattern config, does it require a digit? So if user dials 2001 and there is a dial-peer with "destination-pattern 2001.", is it going to be match?

I will do the lab later when I finish the training however I would appreciate clarification from the experts here. 

Thanks!

Difan

[Mohammed al Baqari]

2001 will match dialpeer 3. I don't think it will match dialpeer 4 because "." is used. If it has been "+" then I would agree but will "." the dialpeer will expect 5 digits starting with 2001

[HARIS_HUSSAIN]

As Stated by Mohammad, 2001 should match 200. and not 2001. as it need 5 digits.

Dial Peers are matched based on best/closest  match

In the example

2001 could match   20[01].   and    200.   and    .T ----> so 200. is more close match as 2001. required 5 digits

2002 could match 200. and 20[01]. and .T   ---> here 200. is more close so it will be used.

2011 could  match 20[01]. and .T    ---> so 20[01]. is more close match

2111 matches .T .

Thanks

Haris

Rate if found useful

[Mohammed Khan]

Looks like typo on destination-pattern should be 2001 for dial-peer 4.

Regards,

Mohammed Noor

[Difan Zhao]

Thanks guys but I think the problem is that "incoming-called" and "answer-address" are not valid for a outbound dial-peer... So I tried config and those POTS dial-peers are down. 

#sh dial-peer voice summary
dial-peer hunt 0
 AD PRE PASS OUT
TAG TYPE MIN OPER PREFIX DEST-PATTERN FER THRU SESS-TARGET STAT PORT KEEPALIVE
11 pots up up .T 0 up 0/3/0
12 pots up up 0 down 0/3/1
13 pots up up 0 down 0/3/2
14 pots up up 2001. 0 up 0/3/3

Here is my config

dial-peer voice 11 pots
 destination-pattern .T
 port 0/3/0
dial-peer voice 12 pots
 answer-address 20[0-1].
 port 0/3/1
 forward-digits all
dial-peer voice 13 pots
 incoming called-number 200.
 port 0/3/2
 forward-digits all
dial-peer voice 14 pots
 destination-pattern 2001.
 port 0/3/3
 forward-digits all

I tried dialing 2001 to 2004, and they all matched dial-peer 11... So I think that we can conclude that it has to be "destination-pattern" to match an outbound dial-peer. What do you think?

Thanks,

Difan

[HARIS_HUSSAIN]

You are right In order to match outbound dial peers, the router or gateway uses the dial peer destination-pattern called_number command. That is the only one used for outbound dial-peer.

Refer this guide for more http://www.cisco.com/c/en/us/support/docs/voice/call-routing-dial-plans/14074-in-dial-peer-match.html

So in Below example  2001 to 2004 matches only the dial-peer 11.

Also i have noticed a typo in the example Image where it says answer-pattern instead of answer-address / destination-pattern.

Also try to change dial-peer 14 as below dial-peer and see what happens !!

dial-peer voice 14 pots
 destination-pattern 200
 port 0/3/3
 forward-digits all

Please mark correct if found useful.

Thanks

Haris

[Difan Zhao]

Thanks for confirmation Haris. So I set the DP 14 to match 200 and when I dialed 2001 or 2002, it matches the DP 11 now which is expected (since 12 and 13 are not even valid). Should I expect to see something different?

Sorry it actually matched DP 14... I first used debug voice dialpeer inout and read the wrong line. Then I used "show call active voice | in Peer" and I see that it is matching 14.

When I called, I called from a phone on a CUCM. There is a SIP trunk between the CUCM and the voice router. So it sends the number all at once. Is that called "en bloc"? Does it make difference than if I called from a phone on the voice router/CME itself? Sorry I do not have a phone handy to test.. Do you mind just explain what will happen and how would I do to avoid this?

Also if you don't mind some other notes from the training that I would like your confirmation. Just can't trust it completely now... So she says

1. When matching an inbound DP, if there are multiple identical matches at last (same incoming-called, and same closest match), then the pick will be random.

2. When matching an outbound DP and when there are multiple identical match, then the lower preference number will win. If it is the same, then lower DP sequence/tag number will win. And these two thing don't play a role for selecting inbound DP. Correct?

Thanks!

Difan

[HARIS_HUSSAIN]

I was trying to show you the example of overlapping Dial-peer and CUCME Behavior.

CUCME matches the dial-peer digit by digit and stops as soon as match is found and routes the calls.

I above scenario when you dial 2001 or 2002 did the correct phone rang on other side?

We should try to avoid Over Lap, if we want to configure overlapping dial plan we can add T  at the end in some scenarios.

1. When matching an inbound DP, if there are multiple identical matches at last (same incoming-called, and same closest match), then the pick will be random

For above query closet match rule is used and then random that is true. In this case a very commonly missed point is that the Dial-peer type plays important role. Incoming Voip calls cannot match POTS dial-peer althout incoming-called number is closet match and vice versa.

 eg  dial-peer voice 10 voip

               incoming-called number 3001

      dial-peer voice 20 pots

              incoming-called number 3001

dial-peer 10 is matches if call comes from 3001 from IP Network.(VOIP)

Dial-peer 20 if call come from 3001 from POTS

2. When matching an outbound DP and when there are multiple identical match, then the lower preference number will win. If it is the same, then lower DP sequence/tag number will win. And these two thing don't play a role for selecting inbound DP. Correct?

For this one, if identical match then lower preference then Random. 

I dont't think lower DP Sequence or tag number win, DP sequence or tag is completely irrelevant.

Yes form inboudn closet match  and random.

For outbound the mechanism is 

Longest match in phone number, explicit preference, random selection [ This is default and can be changed by below command]

dial-peer hunt ?
<0-7> Dial-peer hunting choices, listed in hunting order within each choice:
0 – Longest match in phone number, explicit preference, random selection. [Default]
1 – Longest match in phone number, explicit preference, least recent use.
2 – Explicit preference, longest match in phone number, random selection.
3 – Explicit preference, longest match in phone number, least recent use.
4 – Least recent use, longest match in phone number, explicit preference.
5 – Least recent use, explicit preference, longest match in phone number.
6 – Random selection.
7 – Least recent use.

We can use dial-peer hunt 1 if we want to load balance between two dial-peers.

Please rate and mark correct if found useful.

Thanks

[Difan Zhao]

Thank you! So the "dial-peer hunt" would only affect outbound dial-peer selection, not for inbound, correct?

[HARIS_HUSSAIN]

yes , dial-peer hunt is for outbound dial peer only.