DIAL PLAN
A dial plan is a collection of normalization rules that are assigned to sites, pools or users. which normalizes the dialled No. to E.164 format. There can only be one Dial Plan per site/pool. If one dial plan is assigned to a site and another one to a pool, the pool-level policy will take precedence. If you want more granular control, you can create user-level dial plans.
VOICE POLICY
Voice Policies define the capabilities of the users assigned to it. Capabilities can include call transfer and call forward, among others. Voice policies are assigned to users or sites.
PSTN USAGE
PSTN usage defines the call type that can be made like Local, Long Distance/National, or International. PSTN usages are the link between a voice policy and a route.
ROUTES
A route defines the actual path a call takes on its way out to the PSTN via a defined PSTN gateway. When a user makes a call, a route is selected based on two things: a matching rule (ie. 11-digit numbers starting with +1) and whether that route is part of a PSTN usage assigned to the user.
TRUNK CONFIGURATION
Trunk configuration is the last hop in the Lync environment for the outbound calls before hitting the Gateway. If the GATEWAY is accepting the calls in some particular format then at the Trunk level, trunk translation rules can be created to format the outgoing number
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what is SBA and SBS
Survivable Branch Appliance or Server
SBA - Its an Appliance from Audicodes, Sonus, etc. To provide continuous Enterprise Voice service to branch site users in the event that the link to the central site becomes unavailable. SBA is deployed. SBA is a third-party appliance with Windows Server, Lync Server 2013 Registrar, Mediation Server, and a ISDN card. Recommended for branch sites with <2000 users.
SBS -Its more of like a Standard edition Lync server, that has Registrar and Mediation Server, recommended for branch sites with >2000 users and no resilient WAN, SBS is recommended to be connected to either a PSTN gateway or a SIP trunk to a telephone service provider.
NOTE - SBA is just an SBS + gateway i.e. ISDN card combined into one box. where as SBS does not has any ISDN card, and it is used for larger users.
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Media Bypass
Media bypass it's a feature in lync 2010
The Mediation Server, which is responsible for transcoding audio codecs from one version to another, is considered a media termination point in Lync 2013. In the case of the media traffic traveling to the PSTN, Lync attempts to send the media traffic by way of RTAudio (Microsoft's codec for Lync Audio), but it's intercepted by the Mediation Server and sent to the destination in the G.711 format.
All calls routed beyond the mediation server to:
- Session Initiation Protocol (SIP)/PSTN gateway
- Internet Protocol Private Branch Exchange (IP PBX)
- Internet Telephony Service Provider (ITSP)
traverses through the mediation server, Media bypass refers to removing the Mediation Server from the media path whenever possible for calls whose signaling traverses the Mediation Server.Media bypass can improve voice quality by reducing latency, jitter, media translation, possibility of packet loss, and the number of points of potential failure.
You can also enable media bypass for Lync calls that are routed to VoIP phones by way of IP PBX within an organization.
Note: The Signalling traffic still flow's via the Mediation server.
When media bypass is enabled.
Media bypass and call admission control (CAC) are mutually exclusive. If media bypass is employed for a call, CAC is not performed for that call. The assumption is that there are no links with constrained bandwidth involved in the call.
Media Bypass Requirements
For media bypass to occur, there are a few requirements that must be met in the Lync deployment:
- The Mediation Server's next hop must be able to handle multiple forked responses during the media bypass session. This requirement is very important and shouldn't be overlooked. So, when you're choosing an ITSP or contemplating deploying the newest version of your IP PBX or SIP\PSTN gateway, be sure to ask about its ability to handle forked responses.
- The Mediation Server's next hop must be able to accept the media traffic directly from the Lync client.
Media Bypass Configuration
CSCP > Network Configuration > Global
Always bypass. When you select the Always bypass option, all calls that travel to the Mediation Server will be recognized by the initiating SIP session and all media traffic will be sent directly to the Mediation Server's next hop. The gateways and Lync endpoints must be in the same network site; otherwise, different bypass IDs will be generated. Having endpoints with the same bypass IDs is a key requirement, as it allows the endpoints to communicate with each other.
If you decide to always bypass the Mediation Server, you need to keep the following points in mind:
- Outside (remote) traffic coming through the Edge Server will be on a different network and will not use media bypass.
- When both call admission control (CAC) and media bypass are enabled for a Lync call, media bypass won't occur for that call. (Enterprise Voice first checks to see if the call is configured for media bypass, after which it checks for any CAC restrictions.)
Use sites and region configuration. When you select the Use sites and region configuration option, media bypass works essentially the same way as it does when you select the Always bypass option, with one exception. When both CAC and media bypass are enabled for a Lync call, media bypass will occur for that call. In any given PSTN call, the client subnet is mapped to a particular site, and the bypass ID for that subnet is extracted. The gateway's subnet is mapped to a particular site, and the bypass ID for that subnet is extracted as well. Only when the two bypass IDs are identical will media bypass occur for the call. If the gateway ID and site ID aren't identical, media bypass will not occur. Note that you'd select the Enable bypass for non-mapped sites option when you have branch sites that are part of regions that don't have any bandwidth constraints.
Media Encryption
After you've configured media bypass for the environment, the final task you need to complete is to change the encryption level supported for media traffic. This setting affects how Lync clients talk to the Mediation Server's next hop during a media bypass session. By default, the encryption level for media traffic is set to Required. When you use media bypass, you need to set it to SupportEncryption. That way, if the Mediation Server's next hop supports encryption, Secure Real-Time Transfer Protocol is used. If not, the Real-Time Transport Protocol is used.
There is a bypass id assigned globally or per network site. If the bypass id is exchanged between the client and the mediation server and if the id's match, each other media bypass is possible.
How to enable media bypass cscp > network configuration > Global > here you get option to enable Media Bypass and CAC both
During whose ocs days all the pstn bound calls had to go via the mediation server and the mediation server used to:
remove the encryption from the sip packet, convert from RT audio to G711 (transcoding) and vice viceversa. all these adds latency, jitter, packet loss, etc. & to tackle this and improve voice quality in lync 2010 media bypass was introduced. This enables the lync endpoint that is the lync client to directly talk to gateway that is the lync client can talk in G711
Media bypass is not limited only from end user to gateway but also if a call from end user to another user who is using voip phone by way of ip pbx within the organisation.
But remember the signaling will always go via the mediation server and the actual media will bypass the mediation server or ip pbx.
Media bypass requirement
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The next hop of the mediation server should be able to handle multi forked responses, and the next hop must be able to accept traffic
directly from the Lync client.
Codes used by Lync Client
Baywatch ka hero ka blog on normilazation, etc....
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