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Cisco Unified Border Element (SP Edition) supports E.164 Number Mapping (ENUM).
Feature History for Implementing SNMP
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E.164 Number Mapping (ENUM) is an IETF standard protocol for converting telephone numbers into IP addresses (and vice versa), so that the telephone numbers can be maintained by a DNS server.
The SBC ENUM client is configurable and accepts the ITU standard format for international telephone numbers, E.164: country code, area code, phone number.
The ENUM client translates telephone numbers into standard sip/sips URIs that are resolved by a DNS server and then stored in an SBC routing table. Currently, only IPv4 is supported.
When a telephone number is called, the ENUM client queries the DNS server for a sip/sips URI. The DNS server returns the URI to the ENUM client, and the ENUM client stores the URI in an SBC routing table.
The destination address of a called number is typically derived from the Request URI. However, the destination address may also be derived from other headers in the routing table, such as the To: header or the P-Called-Party-ID: header.
The ENUM Client feature provides the user with the ability to configure a prioritized list of headers. This list may consist of any non-essential SIP headers, including the To: header and the Request URI. Once the list is configured, SBC can derive destination addresses for called numbers from this list of headers.
Destination address headers are stored in the header filter profile MIB table. Destination addresses must conform to the address syntax specification defined in RFC 3261. An address header list may contain a maximum to 10 entries.
The ENUM Client first searches the Request URI. If it does not find a match for the called number, it then searches the header list.
The source address of a calling party number is typically derived from the From: header. The source addresses can be modified using the following configuration.
You can also configure a prioritized list of headers from which the source address for a calling number is derived. This list may consist of any non-essential SIP headers.
Source address headers are stored in the header filter profile MIB table. Source addresses must conform to the address syntax specification defined in RFC 3261. An address header list may contain a maximum to 10 entries.
The ENUM Client feature also provides support for deriving the source number from a prioritized list of headers for calls which have been diverted by another number. If a call has been diverted by another number, the source address must be derived from the diverted-by list of headers. Users can also configure a header action to reject these types of calls.
The user can configure actions to be performed on a target address by configuring a header profile.
The following actions can be configured in a header profile for a target address:
For the SBC ENUM client configuration steps, see the “Configuring ENUM Client” section.
For an example of SBC ENUM client configuration see the “Configuration Examples of ENUM Client Configuration” section.
Additionally, you can also configure the SIP DNS cache, using the following commands:
The sections presents two configurations:
Use the following procedure to configure a call policy for multiple ENUM entries:
6. server ipv4 ip_address [ vrf vrf_name ]
9. server ipv4 ip_address [ vrf vrf_name ]
13. sip header-profile profile-name
14. dst-address
or
src-address
or
div-address
15. header-prio priority-level header-name header-name
17. call-policy-set policy-set-id
18. first-call-routing-table table-name
19. rtg-src-adjacency-table table-id
21. enum enum-id entry (enum) entry-name
22. action next-table goto-table-name
25. enum enum-id entry (enum) entry-name
26. dst-adjacency target-adjacency
28. rtg-dst-address-table table-id
31. dst-adjacency target-adjacency
35. dst-adjacency target-adjacency
Use the following procedure to configure an ENUM Client:
Example 2: Call Policy for Multiple ENUM Entries
Use the following procedure to configure a call policy for multiple ENUM entries: