E1 configuration

[wissamnad]

Hi all,

I need to configure an E1 line on an H323 gateway. I need to use the 32 available channels for making calls. In the channel-group config we have the unframed option so all the 32 channels are being used. When using Pri-group one channel will be lost for framing (time slot 0)?? what is the difference between channel-group and pri-group?

[Dennis Mink]

Here's an example:

controller E1 0/0/0
  framing CRC4 Australia
  pri-group timeslots 1-31
  description description Link To Onramp30

!

network-clock-participate wic 0

!
voice-port 0/0/0:15
input gain -3
output attenuation 3
cptone AU
bearer-cap Speech

!

interface Serial0/0/0:15
no ip address
encapsulation hdlc
isdn switch-type primary-net5
isdn incoming-voice voice
isdn send-alerting
isdn sending-complete
no cdp enable

!

you will need to change this based on your region as well as the slow your card is in.

hope it helps and if it does, please rate

[jijopaul]

Hi

There are two different types of signaling information within the E1 world:

• CCS

• Channel Associated Signaling (CAS)

E1 PRI Uses ccs and other one uses CAS.

CCS

CCS is the transmission of signaling information out of the information band. The most notable and widely used form of this signaling type is ISDN. One disadvantage to the use of an ISDN PRI is the removal of one DS0, or voice channel. In this case, for signaling use. Therefore, one T1 would have twenty-three DS0s, or B-channels for user data, and one DS0, or D-channel for signaling

CAS

CAS is the transmission of signaling information within the information band, or in-band signaling. This means that voice signals travel on the same circuits as line status, address, and alerting signals. As there are twenty-four channels on a full T1 line, CAS interleaves signaling packets within voice packets. Therefore, there are a full twenty-four channels to use for voice. The biggest disadvantage of CAS signaling is that the network uses bits from information IP packets, such as voice packets, to perform signaling functions. CAS signaling is thus often referred to as robbed-bit signaling

[nitsinha · Accepted solution]

Hi Wissam,

The unframed option which you are trying to use will work only if your provider supports unframed data over E1. A G.703 service between two sites can be framed or unframed. An unframed service will run at 2.048 Mbps and doesn’t split the data rate in any way. A framed service, however, divides the 2.048-Mbps data stream into 32 64K timeslots. The first timeslot is used not only to initially set up the framing, but also to carry additional information from one end of the line to the other—often when services go international. This leaves 1.984 Mbps for user data.

In E1, the 16th channel is always reserved for signalling whether or not you are using CAS or CCS. The only difference is that in CCS, the 16th channel in every frame carries the signalling information for the rest of the 30 voice channels whereas in CAS E1, the 16th channel still carries the signalling(CAS information) info but in a frame it carries the signalling for 2nd and 17th channel, the next frame carries signalling for 3rd and 18th channel and so on. Hence in an entire superframe(16 frames), the 16th channel ultimately carries signalling info for all the remaining 30 channels.

Also to find out more info about the difference between E1 CAS and CCS, check the following link

https://supportforums.cisco.com/message/3266323#3266323

Hope that helps

Regards

Nitesh

PS:Pl rate helpful posts

[wissamnad]

In the example that Minkdennis gave, we will be using 31 channels for making calls, is that right?

Nitesh,

Thanks for the helpful info but my question is, if my provider supports unframed data, i will still be able to use the pri-group config but by using the 32 channels for making calls concurrently or ill need to switch to the channel-group unframed configuration to be able to use the Full E1 line (2.048 Mbps)?

[nitsinha]

Hi Wissam,

IMHO i feel you need channel-group config instead of pri-group config if your provider supports unframed data.

Check this doc, may be of your use

http://www.cisco.com/en/US/docs/ios/12_1t/12_1t1/feature/guide/dtg703.html#wp1025616

HTH

Regards

Nitesh    

PS:Pl rate helpful posts