What Protocol Is Used By Cisco Ip Phone To Register With Cm Or Cme

Phone call Routing

CUCM automatically "knows" how to road calls to internal destinations within the same cluster, considering it is configured with the DNs of its associated devices. This can be compared to straight connected networks at a router in IP routing. Route patterns must be configured to route calls to the PSTN. This is equivalent to static routes in an IP router. The call routing table of CUCM is built on registered devices and statically entered route patterns that point to external destinations.

Effigy 11-2 has a bones routing table that consists of the following entries:

■ 2001, 2002, and 2003 are DNs of phones configured in CUCM located at the headquarters.

■ There is a second site, Site one, with CUCM Express and phones using extensions in the range of 3000 to 3999. To be able to route calls to this external organisation, CUCM at the headquarters requires an entry in its routing table for destination 3XXX (Ten is a wildcard digit in road patterns that matches any dialed digit) that refers to the CUCM Limited located at Site 1 via an H.225 torso.

■ At the headquarters, there is a PSTN gateway. To route calls out to the PSTN, a route design ix.! is configured in CUCM, which points to the headquarters PSTN gateway. The exclamation point (!) is a wildcard character that matches on one or more digits. Usage of the dot and the ! is explained in more than particular subsequently in this chapter.

Figure 11-2 Call Routing

408 555-1053

Figure 11-two Call Routing

408 555-1053

Route	Destination
2001	HQ - Phonel
2002	HQ - Phone2
2003	HQ - Phone3
3XXX	Site one
9.!	PSTN

Three calls are placed in the example shown in Figure xi-two:

■ (1) 2001 to 2002: This is an on-cyberspace call. The dialed number 2002 is looked upwards in the call routing table, and the phone call is sent to the advisable IP phone.

■ (2) 2003 to 3001: The dialed number 3001 matches the entry that refers to a trunk pointing to CUCM Limited at Site ane. A telephone call setup message is sent from CUCM to CUCM Limited. This phone call is classified as on-internet because the call is yet on the company IP network.

■ (iii) 2002 to nine one 408 555-1053: This phone call is sent to the PSTN because information technology matches the road pattern 9.!. CUCM will be configured to strip off the PSTN access code 9 before sending the call out to the PSTN through the headquarters gateway. This call is classified every bit off-net because information technology is traversing a PSTN gateway.

Telephone call Routing Tabular array Entries

In the preceding example, the phone call routing table of CUCM was composed of directory numbers and route patterns. Additional routing components tin be configured and are added to the call routing table equally possible telephone call routing destinations. Table xi-2 shows a list of possible telephone call routing table entries. All routing components shown in the table are discussed further in this book.

Table eleven-2 Call Routing Destinations

Routing Component	Description
Directory numbers	Numbers assigned to endpoints and applications. Used for internal routing within a cluster.
Translation pattern	Used to translate the called-party number to a different number.
Road pattern	Used to route calls to remote destinations (PSTN, remote CUCM cluster, and so on).
Hunt airplane pilot	Used to distribute calls (simplified automatic call distribution functionality).
Phone call-park numbers	Allows the holding of a phone call on a number to be retrieved past any other phone in the network.
Meet-me numbers	Allows conference telephone call controller to fix a briefing phone call for multiple parties.

Road Patterns

The CUCM telephone call routing database includes the directory numbers of Cisco IP Phones and estimator telephony integration (CTI) ports configured in the organisation, considering these entries are entered in the IBM Informix Database Server (IDS) by CUCM administration. CUCM does not know about any phone numbers that are configured on external systems. Gateway and trunks allow CUCM to communicate with external systems. CUCM is configured with road patterns that volition be steered through various gateways and trunks to reach the PSTN, remote clusters, and traditional PBXs. The call routing might crave various wildcard parameters to implement robust telephone call-processing logic. Table 11-3 covers the wildcard parameters that road patterns tin use in CUCM.

The @ wildcard is a special macro function that expands into a serial of patterns representing the unabridged national numbering plan for a certain country. For example, configuring a unmarried unfiltered route pattern such as [email protected] with the North American Numbering Plan (NANP) really adds more than 100 individual route patterns to the CUCM dial plan database.

Table 11-iii Road-Blueprint Wildcards

Wildcard	Description
x	Single digit (0-9, *, #)
@	North American Numbering Program
!	One or more digits (0-9, *, #)
[ten-y]	Generic range notation
[Ax-y]	Exclusion range notation
	Terminates admission code
<wildcard>?	Terminates interdigit timeout Matches 0 or more occurrences of whatsoever digit that matches the previous wildcard
<wildcard>+	Matches one or more than occurrences of any digit that matches the previous wildcard

Information technology is possible to configure CUCM to accept other national numbering plans. When this is done, the @ wildcard can be used for different numbering plans, even within the same CUCM cluster, depending on the value selected in the Numbering Program field on the Route Pattern Configuration page.

The @ wildcard tin be practical in several pocket-size and medium deployments, only information technology can go harder to manage and troubleshoot in big deployments. Sure components of the numbering plan tin can be matched by the utilise of road filters.

International destinations are usually configured using the ! wildcard, which represents one or more than digits. In North America, the road pattern 9.011! is typically configured for international calls. In most European countries, the same result is achieved with the 0.00! road pattern.

The ! wildcard is also used for deployments in countries where the dialed numbers tin be of varying lengths. In such cases, CUCM does not know when the dialing is complete and waits for xv seconds (past default) before sending the call. This delay can be reduced in whatsoever of the post-obit ways:

■ Reduce the T.302 timer service parameter. It is best practice to set this value to 4 to 5 seconds to prevent premature transmission of the call before the user is finished dialing.

■ Configure a 9.011! second route pattern ending with an interdigit timeout expiration wildcard. (The # symbol is used for this functionality in about systems.) Instruct the users to dial the # at the cease of their international calls. This activeness is coordinating to pressing the Send button on a cell phone.

The Urgent Priority cheque box in the route-pattern configuration is often used to force immediate routing of sure calls as soon as a match is detected, without waiting for additional digits or the T302 timer to expire. In Northward America, if the patterns nine.911 and ix.[2-9]XXXXXX are configured and a user dials 9911, CUCM usually has to wait for the T302 timer earlier routing the call because farther digits may cause the 9.[2-9]XXXXXX to match (overlapping dial plan). If urgent priority is enabled for the 9.911 route pattern, CUCM makes its routing conclusion equally shortly as the user has finished dialing 9911, without waiting for the T302 timer.

If enbloc dialing is used and the provided number is longer than the urgent pattern, the urgent blueprint is not considered considering all the digits are analyzed as one string.

Translation patterns ever accept urgent priority enabled. The cheque box on the configuration page is grayed out. It cannot exist disabled. The urgent priority information is displayed so that the call-processing logic of a translation pattern can be understood. This tin exist best understood through an example. In a dial plan consisting of a translation blueprint of 100 and a directory number of 1001, extension 1001 would never receive a call from a Skinny Client Command Protocol (SCCP)-based phone. Equally shortly as CUCM matches on 100, the call-processing logic routes the call. In an overlapping punch programme scenario such every bit the one mentioned, CUCM normally waits for additional digits or for the T.302 timer to expire. The differentiating quality is that translation patterns have urgent priority checked and the call is translated as soon equally the digits match.

Route-Pattern Examples

Tabular array 11-4 includes some route-pattern matching examples using various wildcard parameters. The X wildcard matches on the * and # Dual Tone Multifrequency (DTMF) keys even though these are rarely included in phone numbers. The [X-Y] generic range notation matches just 1 digit. A range of [13-59] matches exactly ane digit (a ane, 3, four, 5, or 9). This range does non signify 13 to 59. A comma is an illegal character in the regular expression language used in route-pattern processing.

The 13! appears twice in Table eleven-4, once with a pound sign (#) and in one case without information technology. The ! poses a call routing dilemma. CUCM volition never know when the user is dialing digits because the exclamation signal can match an infinite number of dialed digits. CUCM routes all calls that include ! when the T.302 interdigit timeout expires. The T.302 timer is 15 seconds past default. To alleviate the postal service-dial delay incurred by waiting for this timeout to elapse, a second route pattern can be provisioned with the # to terminate the interdigit timeout. CUCM does not implicitly know how to process the interdigit timeout unless it'south put into a route design. If the pound is not in the route pattern, the user cannot dial this digit unless the PreDot IntlAccess IntlDirectDial DDI is used.

Table 11-4 Route-Pattern Matching Using Wildcard Processing

Road Pattern	Outcome
1234	One exact dialed digit: 1234.
1*1X	Matches dialed digits 1*x to 1*19, ane*ane* and 1*1#.
12XX	Matches dialed digits 1200 to 1299, 12**, 12*#, 12#*, and 12##.
13[25-eight]6	Matches dialed digits 1326, 1356, 1366, 1376, and 1386.
thirteen[13-59]Ten	1310-1319, 1330-9, 1340-ix, 1350-9, 1390-9. The * and # have been excluded for brevity.
13[A3-ix]6	1306, 1316, 1326, 13*half-dozen, xiii#6.
13!	thirteen followed by one or more digits.
13!#	13 followed by i or more digits and so concluded with a #.

Digit Analysis

In practice, when multiple potentially matching patterns are possible, the destination pattern is chosen based on the post-obit criteria:

1. When a user dials the cord 1200, CUCM compares it to the patterns in its telephone call routing table. In this example, there are two potentially matching patterns, 1XXX and 12XX. Both of them match the dialed string, but 1XXX matches a full of thou potential strings (thousand to 1999), whereas 12XX matches only 100 potential strings (1200 to 1299). 12XX is selected every bit the destination of this telephone call considering information technology is the closest match.

2. When the string 1212 is dialed, there are 3 potentially matching patterns: 1XXX, 12XX, and 121X. 121X matches simply ten strings, whereas the other two road patterns lucifer many more strings (explained in the previous step). 121X is the closest lucifer and is selected as the matching design of the call.

When an endpoint goes off-hook, CUCM begins the digit assay procedure. Every number in the call routing database is an initial match unless the phone is configured as a individual line automatic ringdown (PLAR) line. PLAR is used on a directory number to automatically dial a destination and requires the configuration of a calling search space. This functionality is discussed further in Chapter 13, "Calling Privileges."

SCCP phones send their digits one by one every bit they are dialed unless the number is dialed without lifting the handset and the Dial softkey is pressed (hotdial). Hotdial functionality sends all dialed digits in i SCCP telephone call setup message (enbloc) and the behavior of the digit assay will differ. Analog interfaces (FXO, FXS) also send their digits digit by digit, whereas H.323 and ISDN send their digits in one Q.931 setup message (enbloc) past default. The method of forwarding digits is important to understand to determine how digit assay volition lucifer on a route pattern when there is an overlapping punch plan.

As each digit in Figure 11-3 is received, CUCM can reduce the number of potential matches of the dialed digits against the phone call routing database. As shortly every bit an verbal match is found, digit analysis returns a current match, and telephone call routing occurs immediately.

Effigy 11-iii Digit-by-Digit Analysis

m

yard

Dialed Digits

Dialed Digits

Road Patterns

1XXX 10XX

Call Setup

1001

1001

The dial program in Figure 11-3 includes a directory number of 1001, and two road patterns (1XXX and 10XX). The dialed number is 1001, but CUCM has three matching patterns when the third digit is received. When the final digit is received, in that location is only ane design that matches the dialed digits. Because there are no more digits to exist collected, the call is routed immediately.

Digit collection is stopped as soon as an entry in the phone call routing table is matched in its full length and no other (longer) potential matches exist. In Figure xi-four, a user dialed 1111. CUCM interprets the number digit by digit. After the first two digits take been analyzed in

Annotation Session Initiation Protocol (SIP) phones use enbloc dialing in 1 SIP INVITE message by default. Keypad Markup Language (KPML) tin be implemented on Blazon B SIP phones to emulate SCCP digit-by-digit behavior. If digits are received enbloc, the unabridged received dial string is checked confronting the call routing database. This differs profoundly from the digit-by-digit analysis used by SCCP-controlled phones.

this example, only one potential friction match is left (the first entry) because all other entries in the phone call routing table crave a different digit than one at the second position. CUCM continues collecting digits until it receives iv digits (1111); now the starting time entry is fully matched and used to route the call.

Figure xi-4 Digit Collection Example

User Dial Cord: 1111

In Figure 11-5, the user dialed 1211. After interpreting these digits, CUCM has two matches: 121X and 1[23]20 and no boosted potential matches that are longer (which would require waiting for more digits). Digit drove is stopped, and the closest-lucifer routing logic is applied. Route pattern 121X represents ten potential matches, and route design 1[23]Twenty represents 100 potential matches that showtime with 12. The first entry is the closest match and volition be used to road the call.

Figure 11-five Closest-Match Routing Example

Effigy eleven-five Closest-Match Routing Example

In Figure 11-6, a user dials 1311—CUCM has 3 potential matches at this time: 13[0-4]10, i[23]Xx, and 13!. The last entry represents a variable-length route design because it tin potentially friction match on more digits. CUCM has to look because the user might provide additional digits. CUCM will not wait an indefinite time for additional digits, nevertheless. After the T.302 interdigit timer expires (15 seconds by default), CUCM attempts to road the telephone call based on the closest-friction match logic. If there are no other matching patterns at this time, CUCM issues a reorder tone or a recorded annunciator message to the calling party. In this example, there are two matching route patterns, but 13[0-four]X is the closest pattern representing only ten possible numbers, whereas i[23]20 has 100 potential matches, and thirteen! represents an unlimited number of potential matches.

Assume that the user dialed only three digits: 131. CUCM would match all three route patterns at this fourth dimension, but afterwards the interdigit timeout expired, only one route blueprint would lucifer: 13!.

These wildcards can be helpful when creating a PSTN punch plan in North America similar that in Table 11-five. Almost of the route patterns include a 9 as an access lawmaking and a dot (.) used as a delimiter for digit-stripping rules. Later in this chapter, nosotros discuss digit discard instructions (DDI), which allow CUCM to strip digits preceding the dot (admission code).

Figure 11-6 Interdigit Timeout

Figure 11-six Interdigit Timeout

Tabular array eleven-five N America PSTN Dial Plan

Route Blueprint	Description
911	Emergency telephone call routing without access code
9.911	Emergency telephone call routing with admission code
ix.[2-8]11	3-digit service codes (for example, 411 for information)
ix.[2-9]Xx XXXX	vii-digit local dialing
9.[2-ix]20 [2-nine] XXXX	10-digit local dialing
9.1[two-ix]XX [two-9]XX XXXX	11-digit long-altitude dialing
ix.011!	International dialing (variable-length dialing)
nine.011!#	International dialing (variable-length dialing with interdigit termination)

Go on reading here: Digit Forwarding

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