48
February 2012
February 2012
Michael Mauck
National Account Manager
Introductions Fundamentals of SIP Avaya SIP Technology Real Life Experiences System/Session Manager Demo Roadmap – why SIP
Rob Nixon
VP of Operations
What is SIP?
SIP Components
IETF Standard
Application Layer protocol
Based on HTTP and SMTP
Methods-based Protocol
RFC 3261 describes Session Initiation Protocol (SIP), an application-layer control (signaling) protocol for creating, modifying, and terminating sessions with one or more participants. These sessions include Internet telephone calls, multimedia distribution, and multimedia conferences.
Layer Name TCP/IP Protocols
7 Application NNTP, SIP, SSI, DNS, FTP, Gopher, HTTP, NFS,
NTP, DHCP, SMPP, SMTP, SNMP, Telnet, RIP, BGP
6 Presentation MIME, SSL, TLS, XDR
5 Session Sockets. Session establishment in TCP, RTP
4 Transport TCP, UDP, SCTP, DCCP
3 Network IP, IPsec, ICMP, IGMP, OSPF
2 Data Link PPP, SBTV SLIP, PPTP
1 Physical X.25 (X.21bis, EIA/TIA-232, EIA/TIA-449, EIA-530, G.703)
SIP is designed similar to the HTTP request/response transaction model
A transaction consists of a client request that invokes a particular method or function on the server and at least one response
SIP reuses most of the header fields, encoding rules and status codes of HTTP, providing a readable text-based format
A signaling standard that can connect and control communications sessions between applications
Independent of media type or the function performed by the end applications
SIP is known as a “methods-based” signaling protocol because it provides the methods to connect, signal, and control sessions ◦ In that sense, SIP is quite different from a “functionally
based” signaling protocol, such as Q.SIG, which is used not only to establish sessions, but also to define the specific features those sessions can support.
User Agents
Registrars & Location Services
Proxy Servers
B2BUA
Redirect Servers
Presence
SDP
User Agent Clients and User Agent Servers are logical entities and both reside in a UA device, allowing peer-to-peer sessions using a client-server protocol.
◦ (UAC) send SIP requests and receive responses to requests
◦ (UAS) receive SIP requests and send responses to requests
Servers that maintain a repository of the current network locations of users within a domain
Registrars rely on Location Services ◦ A database mapping of a user’s SIP URI (Universal
Resource Identifier) with one or more contact addresses or numbers for the user.
IP Address: 192.168.1.156 sip:[email protected] sip:[email protected];user=phone sip:[email protected]
Registration
Bkarch has registered. Now I know that sip:[email protected]
is contactable at sip:[email protected] and
sip:[email protected];user=phone
Registry
SIP Server
The SIP standard defines SIP proxies as “elements that route SIP requests to User Agent Servers (UAS) and SIP responses to User Agent Clients (UAC)
A request may traverse several proxies on its way to a UAS.
I want to call Adam Smith at Comcast.
DNS
I don’t know have [email protected]
registered, let me check DNS
Sunturn
Comcast
Registry
Registry
SIP Server
SIP Server
A B2BUA is a logical entity that receives a request and processes it as a UAS. It then acts as a UAC and generates requests. Unlike a Proxy Server, it maintains dialog state and must participate in all requests sent on the dialogs it establishes.
The B2BUA is similar in many ways to a Proxy server, but has tighter control over the dialog and does not have the limitations of the SIP standard on the Proxy (for example, a Proxy cannot disconnect a call or alter the messages).
A redirect server receives SIP requests and responds with 3xx (redirection) responses, directing the client to contact an alternate set of SIP addresses.
I want to call Adam Smith at Verizon
NA
Sunturn
Verizon NA
Verizon APAC
Adam Smith is working a
special project in
APAC
DNS
DNS
Registry
SIP Server
SIP Server
SIP Server
Presence gathers information from multiple providers and then shares it between those providers and any other applications that are interested in it.
RFC 3265 – (SIP)-Specific Event Notification
Registry
SUBSCRIBE to sip:[email protected]
Brian is not available. I will remember to update this
subscriber when his presence status changes.
200 OK
200 OK
NOTIFY sip:[email protected] Not Available
200 OK
NOTIFY sip:[email protected] Available
Brian is available.
SDP is the protocol used to describe multimedia session announcement, multimedia session invitation and other forms of multimedia session initiation. SDP packets usually include the following information: ◦ Session information - Name and Purpose, Timer,
Bandwidth and Contact Info
◦ Media information - Type, Transport Protocol Media Format, Multicast Information
Brian Karch
Sales Engineer
System Manager
Session Manager
Common Applications
System Manager Centralized Management
Centralized Alarming
Centralized Logging
Profile Management
Application Sequencing
Station Profile
Messaging Profile
Session Manager ◦ SIP Routing Engine
◦ SIP Integration Platform
◦ Geographically Dispersed
Branch Session Manager ◦ Simultaneous Registration (Endpoint)
◦ Survives to CM LSP
Common Applications ◦ Session Border Controller
◦ Video Integration
◦ 3rd Party Integration
◦ Endpoints
Why ? ◦ Scalable
◦ Resiliency (Active / Active)
◦ Consolidated Network Infrastructure
TDM vs Ethernet
◦ Solution Development and R&D
Mike Baker
Software Engineering Manager
SIP Trunks ◦ The Myth: “You already have our <insert vendor
here> data circuit; we can add SIP voice to that no problem. We work with Avaya all the time.”
◦ The Reality:
Requires Voice/Data/LAN-WAN/Security input
Requires clear network topology and access to elements
Requires supported App Note for any help from Avaya
Requires SBC for BEST PRACTICES
SIP Trunks ◦ The Myth: “Our <insert vendor here> PBX can talk
SIP to yours no problem. We work with Avaya all the time.”
◦ The Reality:
Not all vendors comply with RFC 3261
Most require significant customization
Most require adaptations
Adaptations don’t cover all scenarios
SIP Stations ◦ The Myth: “This cheap <insert vendor here> phone
uses SIP. They say they connect to Avaya all the time.”
◦ The Reality:
Some customization required on Avaya side
All non-Avaya devices require mostly manual and frequently tedious configuration on the device
Feature sets are still limited in varying degrees for ALL SIP phones
Your friendly neighborhood “SIP MythBusters”
Mike Baker
Software Engineering Manager
Demo Environment ◦ S8300 CM R6 /G700 Evolution Server (PBX)
◦ S8800 System Manager R6
◦ S8800 Session Manager R6
◦ One-X SIP softphone
◦ ADVD SIP hardphone
◦ 9630 SIP hardphone
◦ Avaya/Nortel 4550 ethernet switch
Rob Nixon
VP of Operations
Standards based
Ubiquitous
IMS
RFC Description
RFC 2976 The SIP INFO Method
RFC 3261 SIP: Session Initiation Protocol
RFC 3262 Reliability of Provisional Responses in the Session Initiation Protocol (SIP)
RFC 3263 Session Initiation Protocol (SIP): Locating SIP Servers
RFC 3264 An Offer/Answer Model with the Session Description Protocol (SDP)
RFC 3265 Session Initiation Protocol (SIP)-Specific Event Notification
RFC 3311 The Session Initiation Protocol (SIP) UPDATE Method
RFC 3325 Private Extensions to (SIP) for Asserted Identity within Trusted Networks
RFC 3428 Session Initiation Protocol (SIP) Extension for Instant Messaging
RFC 3515 The Session Initiation Protocol (SIP) Refer Method
Dozens of manufacturers of endpoints—hard, soft, mobile
Accepted standard for flexible trunking
3GPP and IMS deliver IP Multimedia to users ◦ IMS defines a framework that enables the
convergence of voice, video, data and mobile network technology over an IP-based infrastructure
◦ Users register to IMS directly via SIP—mobile phones, PDAs, computers, wireless, etc.
IMS is not intended to standardize applications but rather to aid the access of multimedia and voice applications from wireless and wireline terminals, i.e. create a form of fixed-mobile convergence (FMC)
IMS is intended to create a horizontal control layer that isolates the access network from the service layer
Named Sequenced
• Caller must dial a special access number to trigger the feature
• Caller is oblivious—does not know if a feature will be triggered or not
• A Named Application is always the SIP End Point
• A Sequenced App is often a mid-way point
• Named apps are dependent upon NRP—Session Manager doesn’t know what will happen/where, it just knows that the digits dialed route to X
Application sequencing is the routing engine for the SIP sessions, adding applications into the session before completing the setup of the session
Enables unified communications (UC) services to be applied to any user over any network on any device
Can be part of origination, termination, or both
App Server
e.g. Call Filtering
App Server
e.g. Personal Assistant
App Server
e.g. Call Recording
App Server
e.g. Call Billing
SIP provides economies
SIP creates opportunities for best in class
SIP puts communications availability into an end user’s hands
SIP will continue to become a ubiquitous methodology for setting up multimedia sessions in, and between, the wireless, service provider, and Enterprise market space
Pam Drennan
Director of Sales
