GK technology prefix !

[Jonn cos]

Hi all.

I am having difficulty understanding technology prefix. What i have read so far is that, we group GWs according to their capabilities. Lets say 2# is assigned to voice gateways so now what ? i have read that caller will append 2# if he wants to make use of it but why would a normal caller will bother with that ??

I am really not getting for who this technology prefix is for ?

[clileikis]

Hi Jonn,

Check out the following link:  http://www.cisco.com/en/US/tech/tk1077/technologies_tech_note09186a00800a8928.shtml#tp

Technology Prefixes

A technology prefix is an optional H.323 standard-based feature, supported by Cisco gateways and gatekeepers, that enables more flexibility in call routing within an H.323 VoIP network. The Cisco gatekeeper uses technology prefixes to group endpoints of the same type together. Technology prefixes can also be used to identify a type, class, or pool of gateways.

Cisco gatekeepers use technology prefixes to route calls when there is no E.164 addresses registered (by a gateway) that matches the called number. In fact, this is a common scenario because most Cisco IOS gateways only register their H.323 ID (unless they have Foreign Exchange Station (FXS) ports configured). Without E.164 addresses registered, the Cisco gatekeeper relies on two options to make the call routing decision:

• With the Technology Prefix Matches option, the Cisco gatekeeper uses the technology prefix appended in the called number to select the destination gateway or zone.

  
  

• With the Default Technology Prefixes option, the Cisco gatekeeper assigns default gateway(s) for routing unresolved call addresses. This assignment is based on the gateways' registered technology prefix.

  
  

Users won't actually dial technology prefixes, they will be pre-pended to numbers (check the link for an example of configuring it on a dial-peer) for a Gatekeeper to properly route calls if E.164 addresses are not registered to a gatekeeper. 

There 's a gatekeeper path selection flow chart about a quarter ways down the page on the link above that you should take a look at that will explain the Gatekeeper call routing behaviour and should hopefully make it a bit clearer.

HTH,

Chris

[Priyadarshini B.T]

Hi Jonn,

The first concept is the gatekeeper technology-prefix , which is  the core of the gatekeeper dynamic call-routing process. Look at the  tech-prefix as a special label used to group together a set of VoIP  gateways. The gateways may register their technology prefixes with the  gatekeeper dynamically, or you can map the prefixes to the VoIP gateways  statically. The gatekeeper looks at the gateways registered under the  same tech-prefix to be members of  a single “gateway pool”. Now, recall  that tech-prefix is just a part of the dialed number. Whether the called  number prefix is actually a technology prefix, is decided by the  gatekeeper, when it matches the dialed number against the database of  the local registered/configured prefixes. There is nothing in the dialed  number itself, that designates the part of the dialer string as a  technology prefix.

A special instance of tech-prefix is the default-techology prefix. When you have one or more tech-prefixes registered by gateways  or configured statically, you can designate one of them as “default”.  The gatekeeper will “route” the incoming call to this prefix if it  cannot match the incoming call against any registered/configured  tech-prefixes. Notice that this happens even though the dialed number  prefix does not match any of the local technology prefixes.

hope this helps.

[Jonn cos]

Thanks alot guy for such detailed replies. Kindly clear my last confusion,

In real world, lets say if i group voice gateways with tech prefix 2#, does the user have to append this prefix when he dials any number ?

[Marwan ALshawi]

Hi Jonn

no the user dose not need to dial the tech prefix becuase you can either add it with the gateway registration to the GK settings

using the command bellow in the Gateway

h323-gateway voip tech-prefix 2#

http://www.cisco.com/en/US/tech/tk1077/technologies_tech_note09186a00800a8928.shtml#t8

or you can have it configured on the dia-peer level

dial-peer voice 1 voip

destination-pattern xxxxxx

session target ras

tech-prefix 2#

HTH

pls rate the helpful  posts

[Marwan ALshawi]

HI John

GK uses the tech-prefix to match check against the local zonez and local registered prefixes ( Does the zone prefix match? Yes. Set the target-zone to equal the local zone ) if not it i will look into other options before rejecting the call such as zone prefix, default GW, remote zone/GK

however it is not must to be dialed or used by GW or users

for example if you have a GK with local zones without a tech-prefix configured in the GK

in the GW also you dont have to configure the tech-prefix and the process will be something like the bellow assuming no zone prefix configured as well the GK

GK-A receives ARQ from GWY-A1.

1. Does the technology prefix match? No

   
   

2. Does the zone prefix match? No

   
   

3. Is the arq reject-unknown-prefix command set? No, target-zone equals local zone.

   
   

4. Is the target-zone local? Yes

   
   

5. Was a technology prefix found in step 1? No

   
   

6. Is the target address registered? Yes. Send ACF

   
   

however if you have a tech-prefix configured and you want ot used for zone prefixes in the GK you can add it to the GW registration config or in the dialpeer NO need for the user to dial the 2# for example unless you do not configure it correctly, also be aware that when a call matched against a number in GW with tech prefix forxample 2#123456 once the GW locate the destination GW/zone it will be recieved by GW to as 2#123456 and in that GW you need to have a translation rule to remove this 2# from the called number

one more point

if you have a GW1 registered with GK using tech-prefix 2#

GW2 not configured with Tech prefix

GK configured with default-tech-prefix of 2#

then the GK will route calls without a technology prefix match to the default technology prefix gateways

in this case GW2 no need to be configured with tech prefix

for more details and examples please refer to the bellow useful linke

http://www.cisco.com/en/US/tech/tk1077/technologies_tech_note09186a00800a8928.shtml

HTH

if helpful Rate