Also explain when do we use this feature (Please explain for both VOIP & Traditional telephony system)? Why we use this feature? what problems shall we face if we don't use '9' before making outbound call? explain this in reference to North American Numbering Plan.
Outbound Call – Why and When to Use Digit ‘9’ Before Making an Outbound Call
voicevoip
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Mixing versions like this, depending on which version of CME and CUE you are using, will work in some instances.
In your particular case however, it appears that the answer is no.
CME 8.6 will only work with CUE versions 7.3, 7.4, 8.5, and 8.6.
Since you're talking about a plain NM-CUE in a 2811, that module will only support up to CUE version 7.0. Your best bet for a hardware solution would be the NME-CUE, which can support up 8.6 in my testing.
The other option, depending on your other requirements for 15.(1)M4, would be to roll back to an older IOS on the 2811 for an older CME.
See the Cisco Unity Express Compatibility Matrix and the Cisco Unfied CME and Cisco IOS Software Compatability Matrix for more information.
QoS is all about fairness, as you define it. There are multiple parts to QoS.
There is layer-2 QoS, which uses 802.1P to set the COS bits in layer-2 headers for layer-2 domains. Cisco switches have full COS marking, but limited layer-2 queuing.
There is layer-3 QoS, which uses the TOS bits in IP packets. Cisco routers have pretty extensive layer-3 queuing capabilities.
You also have things related to queuing, e.g. shaping and policing. You will need to decide on policies for these.
First you need to classify the traffic. Basically marking the packets with separate TOS/DSCP marking for the different traffic types. This is best done as close to the traffic source as possible, and Cisco switches can do this as traffic enters the switch from the host.
Once you have classified and marked the traffic, you can apply your fairness doctrine. In your case, it sounds like you want a priority queue on the WAN interface for the VoIP traffic. You will need to decide which percentage of the bandwidth to dedicate to VoIP, and configure your queuing accordingly.
Understand that your QoS markings and policies will not be honored on the Internet, and that you have no real control over incoming traffic, since by the time you see the incoming traffic, the bandwidth has already been used. Since VoIP is a two-way conversation, you can have perfect QoS on your network, but still get crappy VoIP calls because there is no QoS on the Internet, and your incoming WAN link can be saturated, and your QoS policies have no real effect on that.
QoS is a really huge subject, too large for this site. You would need to provide a lot of information about your devices and their configurations, and make some decisions about a lot of things. There is no real way to say, "this" is the answer to how you should accomplish what you want.
Best Answer
In traditional public telephony in USA exists the North American Numbering Plan that defines this:
If you call whitin the same area code you don't need to dial it, so you can dial NXX-xxxx (7 digits)
If you call to another area code you need to dial it, so you have to dial NPA-NXX-xxxx (10 digits).
If you need to call to a foreign country you have to use the international prefix: 011 (for example: 011 + country code + number).
In addition, the NANPA defines N11 codes:
The administrator of a private PBX has a group of internal extensions with their own numeration. For example [300-399 accounting], [400-499 sales], [800-899 management], etc.
To determine easily if an user is dialing to another extension or to an outside number a group of rules can be set in this way:
User dials a number beginning with a number between 2 and 8 -> Internal call (connect directly to the number dialed).
Dial a number beginning with 9 -> External (ditch the '9' and send the rest of the numbers to the local telco).
0 seems to be a good choice, however can be confusing because the international prefix
9 is a good choice. The only restrictions are:
Modern PBXs can be set using rules by number length, so the rules can be modified to:
Dial 911 -> Emergency Call -> Send the call
Dial a number beginning with 9 plus more than 2 digits -> External (ditch the '9' and send the rest of the numbers to the local telco).
In that way, both numbers work (911 and 9911).