Transcript Number portability

TRIP, ENUM and Number Portability
Nicklas Beijar
[email protected]
Nicklas Beijar - TRIP, ENUM and Number Portability
Slide 1
Contents
TRIP, ENUM and Number Portability
1.
2.
3.
4.
5.
6.
7.
Current situation
Problem description
TRIP
ENUM
Scenarios
Number portability
Conclusions
Nicklas Beijar - TRIP, ENUM and Number Portability
Slide 2
Current situation
Terminal location
• End terminal located with signaling protocol and DNS
”user@host”, ”user@server”
• Mapping from name (E.164, URL, e-mail) to address (IP address)
• Mapping stored in location server (gatekeeper, signaling server)
• Manually configured or obtained through registration
• Directory servers (ULS, ILS)
E.164 numbers selected for IP Telephony by TIPHON
• Can be entered with numeric keypad
• Users don’t need to know if the receiver is a IP or PSTN subscriber
Nicklas Beijar - TRIP, ENUM and Number Portability
Slide 3
Current situation
Gateway location
• Similar to terminal location, number@gateway
• Gateway selected manually by caller or by signaling server
• New selection if gateway is unavailable
Number portability
• Change service provider, location or service type without changing
telephone number
• IP Telephony -> number portability between PSTN and IP
• Currently available in the PSTN only
• Mapping from directory number to routing number (or routing prefix)
• Routing number has hierarchy
• Mapping performed by Intelligent Network (IN)
Nicklas Beijar - TRIP, ENUM and Number Portability
Slide 4
Problems
Given a phone number corresponding to a specific host on the IP
network, determine the IP address of the host.
 Terminal location problem
Given a phone number corresponding to a terminal on the PSTN,
determine the IP address of a gateway capable of completing calls to
that phone.
 Gateway location problem
Nicklas Beijar - TRIP, ENUM and Number Portability
Slide 5
Problems
• Mappings are not distributed between signaling servers and
location servers
• E.164 numbers cannot be used globally
• Users must select gateway manually
• Which gateways are available and suitable for this call?
Nicklas Beijar - TRIP, ENUM and Number Portability
Slide 6
Gateway selection criteria
•
•
•
•
Location
Business relationships
Policies
Features
• Signaling protocol
• Codec
• Service
• Capacity
Nicklas Beijar - TRIP, ENUM and Number Portability
Slide 7
TRIP
• Telephony Routing over IP
• IETF protocol, still at draft stage
• Distributes routing information between location servers
• Information about gateways and the numbers reachable
through them
• Routes to gateways and signaling servers
• Modeled after BGP-4
• Gateway selection driven by policies
• Interdomain protocol between Internet Telephony Administrative
Domains (ITAD)
• Interdomain synchronization based on SCSP and OSPF
• Information transported as attributes of the UPDATE message
• Expandable
Nicklas Beijar - TRIP, ENUM and Number Portability
Slide 8
TRIP attributes
Name
Description
Withdrawn routes
List of telephone numbers that are no longer available.
Reachable routes
List of reachable telephone numbers.
Next hop server
The next signaling server on the path towards the destination.
Advertisement path
The path that the route advertisement has traveled.
Routed path
The path that the signaling messages will travel.
Atomic aggregate
Local preference
Indicates that the signaling may traverse ITADs not listed in the
routed path attribute.
The intra-domain preference of the location server.
Multi exit disc
The inter-domain preference of the route if several links are used.
Communities
For grouping destinations in groups with similar properties.
ITAD topology
For advertising the ITAD topology to other servers in the same ITAD.
Authentication
Authentication of selected attributes.
Nicklas Beijar - TRIP, ENUM and Number Portability
Slide 9
Structure of a TRIP node
Local TRIB
Decision Process
Adj-TRIBs-In
(internal LSs)
Adj-TRIBs-Out
Ext-TRIB
Adj-TRIBs-In
(external peers)
Nicklas Beijar - TRIP, ENUM and Number Portability
Local Routes
Slide 10
TRIP for gateways
• TRIP-GW
• Exports routing information from gateways to location server
• New attributes
• Circuit capacity
• DSP capacity
• Lightweight
• Send-only mode
• No databases
• Compatibible with TRIP
Nicklas Beijar - TRIP, ENUM and Number Portability
Slide 11
ENUM
•
•
•
•
tElephone NUmbering Mapping
RFC 2916
Maps E.164 numbers into Uniform Resource Identifiers (URI)
The URIs represent different ways to contact a host
• SIP, H.323, TEL, email, ...
• Uses the Domain Name System (DNS)
• E.164 number rewritten as a domain name:
->
+358-9-4515303
3.0.3.5.1.5.4.9.8.5.3.e164.arpa
Nicklas Beijar - TRIP, ENUM and Number Portability
Slide 12
Example NAPTR records
$ORIGIN 3.0.3.5.1.5.4.9.8.5.3.e164.arpa.
IN NAPTR 10
10 “u” “sip+E2U”
“!^.*$!sip:[email protected]!”
.
IN NAPTR 100 10 “u” “mailto+E2U”
“!^.*$!mailto:[email protected]!” .
IN NAPTR 100 10 “u” “tel+E2U”
“!^.*$!tel:+35894515303!”
Nicklas Beijar - TRIP, ENUM and Number Portability
.
Slide 13
Example reachme service
Sample top level delegations from ITU:
3.3.e164.arpa
8.5.3.e164.arpa
IN NS ns.FR.phone.net.
IN NS ns.FI.phone.net.
;France
;Finland
Sample national delegations:
5.4.9.8.5.3.e164.arpa.
IN NS ns.ServiceProviderX.net.
Sample service provider’s configuration:
1.5.4.9.8.5.2.e164.arpa. DNAME 1.5.4.9.8.5.2.ns.hut.fi.
Sample service registrar configuration:
*.1.5.4.9.8.5.2.ns.hut.fi.
IN NAPTR 100 10 ”u” ”ldap+E2U”\
“$!ldap://ldap.hut.fi/cn=\1!” .
Nicklas Beijar - TRIP, ENUM and Number Portability
Slide 14
Call from IP-based network to PSTN
Voice path
ENUM query
Location server query (LDAP)
SIP Client
SIP
Server
POTS
Phone
PSTN
Nicklas Beijar - TRIP, ENUM and Number Portability
LS
DNS
IP-based
Network
Gateway
Slide 15
Call from PSTN to IP-based network
POTS
Phone
PSTN
SIP Client
SIP
Server
Voice path
ENUM query
Nicklas Beijar - TRIP, ENUM and Number Portability
Gateway
IP-based
Network
DNS
Server
Slide 16
Number portability
•
Scenarios for hybrid PSTN-IP networks:
1. The number moves within the PSTN.
2. The number moves between PSTN and IP.
3. The number moves within the IP network.
•
•
ENUM allows the mapping to be modified at different levels
Another gateway may be more suitable
 In most cases, information in ALL protocols must be updated
Nicklas Beijar - TRIP, ENUM and Number Portability
Slide 17
Conclusions
• TRIP solves the gateway location problem
• Distributes routing information between location servers
• ENUM solves the terminal location problem
• Provides mapping between names to addresses
• E.164 numbers
• In the PSTN, number portability implemented with IN
• Number portability can be implemented with TRIP and ENUM
• Still missing
• Automatic updating of infomation between TRIP, ENUM and IN
• Gateway location for the PSTN
 CTRIP
Nicklas Beijar - TRIP, ENUM and Number Portability
Slide 18