service advertisement framework

1

SAF –Service Advertisement Framework

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Module Agenda

Introduction to Service Advertisement Framework

Overview of the SAF Network

Overview of the SAF Client-Network Interface

SAF Service - Call Control Discovery (CCD)

Deployment and Configuration of SAF

Review of SAF Features and Benefits

Summary of SAF

3

Module Objectives

Upon completion of this module, you will be able to:

Describe what the SAF feature is and how it benefits the network

Identify the components that make up the SAF network

Explain what Call Control Discovery is used for and how it helps Cisco UC networks

Describe the benefits of Call Control Discovery

Configure SAF with the necessary commands to enable the feature

Explain the benefits of the Service Advertisement Framework feature

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Introduction to SAF

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New technologies and applications wereoften deployed as overlays

Many networks utilize static configurations – what happens when:

– The service location changes?

– The service connectivity is lost?

– Network connectivity is lost?

Problems with static configurations:

– Configuration complexity

– High operational cost

– Deployment speed

The network needs to leverage dynamic routing capabilities to help these services communicate and adapt to changes

The network needs to provide a foundation for service awareness and allowapplications to be discovered without user

Today’s IP Network & Static Configurations

6

Technology Description

Wide Area Bonjour

Relies on DNS, which (depending on the deployment model) may be a potential single point of failure. DNS may also not respond well to the dynamic nature of some applications.

UDDI/WS-Discovery

Central directory for service registration and discovery: potential single point of failure. Represents an overlay on the network (i.e. no real network integration).

PNRP + Other P2PDistributed database, but relies on intelligence and load on the clients.

Service Location Protocol (SLP) Uses multicast to announce services. Can be very chatty. Scalability issues.

Active Directory / LDAPStores service information in distributed directory. Client uses RPC-based lookup API. No network integration. Not widely deployed

DNS SRVUses the DNS SRV record type to store service information including priority and weight

Existing Service Discovery Solutions

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Service Advertisement Framework - SAF

SAF is: Network-based, bandwidth efficient approach to service advertisement

Leverages Cisco routing technology - works w/ EIGRP, OSPF, RIP

3 main components:

1. The SAF Network –propagate service advertisements

2. The SAF Client-Network Interface –publish and subscribe to services

3. The SAF Services –e.g., Call Control Discovery

SAF Network

SAF Services

SAF Services

SAF Services

Client-Network

Client-Network

Client-Network

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Traditional Service Discovery vs. SAF

Traditional Service Discovery SAF = Auto Service Discovery

Most network services and applications are

implemented as overlay systems on top of

the network which provides operational

complexity

True network integration, simplifying network

design and services availability

Requires separate configuration

management and coordination between the

network and service

Unified interface between network and

services resulting in simplifying configuration -

speeds new service deployments

Limited scalability and resiliency compared to

the IP Network

Uses EIGRP - leveraging Cisco routing

technology with proven scalability and fast

converging characteristics, similar to the IP

network - adaptive to service and network

changes

9

SAF Component Description

SAF Forwarder Router feature – provides relationship between

client and framework, stores service information

and propagates it to other Forwarders

SAF Client Any application wishing to advertise a service to

the network or request a service from the network

or both

SAF Service Any information that a SAF Client wishes to

advertise or consume

SAF Advertisement Carries service information, consists of SAF

Header and Service Data

Non-SAF Node Any router that does not run the SAF protocol

Service

SAFHeader

SAFService Data

SAF Network Elements

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SAF Forwarder

SAF Forwarder receives services advertised by SAF Clients

SAF Forwarder:

–Ensures reliable delivery of service advertisements

–Maintains knowledge of path redundancy

–Is scalable

–Minimizes network bandwidth use with targeted mcast & unicast

Cisco SAF Forwarder propagates Service Ads to other Cisco SAF Forwarders

Forwarder provides relationship between SAF Clients & the SAF Network

Forwarder receives Service Advertisements and stores a copy before forwarding the advertisement to its neighbor SAF nodes

If a Client removes a service or disconnects from the Forwarder node, the node will inform the framework about the down services

Forwarder removes Client‟s advertisements from the framework

Transitive Forwarder is a Forwarder with no clients connected

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SAF Client

SAF Client is a producer of services, a consumer of services, or both

SAF Client establishes a peering relationship with the Cisco SAF Forwarder

SAF Client publishes advertisements to the Cisco SAF Forwarder that contain information about the service it offers

The Cisco SAF Forwarder advertises all services published by the Cisco SAF Client

When asking for a service, SAF Client sends a services request notification using a subscribe request

In response to a services request, SAF Forwarder sends the current set of services to the SAF Client

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SAF Services

Any information that a SAF Client wishes to advertise that can then be used by other SAF Client applications

Any information that a SAF Client wants to consume

SAF Services are announced using a SAF Service Advertisement consisting of service data

First client application to use SAF is Call Control Discovery (CCD) - UC

CCD uses SAF architecture to distribute and maintain information about Directory Numbers

SAF takes away static configurations for dial plan distribution

CCD with SAF enables dynamic dial plans for a Cisco Unified Communication system

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New York

CMEAdvertise:

+1972555....

Nice

CME

London

CallManagerSan Jose

Call Manager

Advertise:

+3349988....

Advertise:

+1408555....

+1415234....

Advertise:

+4422334....

CCD & SAF Propagating Reachability for Call Agents

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– Used by Forwarders to propagate Advertisements

– Identifies service type, unique instance, and advertiser

– Metrics used to avoid loops

– Service-specific information

– Meaningful only to clients of the given service

– Transparent to Transitive Forwarders, only interested in the Header

SAF Header SAF Service Data

Service ID

Metrics

101 2 1.2.3.4

...

...

IP Address Port

Client Data

Length

SAF Advertisement

SAF Advertisement intended to provide sufficient information about the Service

SAF Client will send a SAF Advertisement to announce its Service

SAF Forwarder sends SAF Advertisement to Client when Client needs Service

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Non-SAF Node

To enable SAF within a network, only a subset of routers need to be configured as SAF Forwarders

Networks of Non-SAF capable routers and SAF capable routers can run any IP routing protocol

Non-SAF Node is any router that does not run the SAF protocol

„Dark Nets‟ are domains of one or more routers that do not have SAF; e.g. MPLS or Internet Service Provider

Cisco SAF messages are IP-based and therefore can traverse Non-SAF nodes and Dark Nets

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SAF Features and Benefits

SAF provides a framework that allows networking applications to automatically discover networked services

Automated discovery of services replaces the manual entry of complex configurations

SAF allows applications to advertise their services

Cisco SAF allows user to create a configuration once, and then have it propagate to all devices that require the information

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The SAF Network

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SAF External

Client

SAFForwarder

Non-SAFCloud

SAF TransitiveForwarder


SAF Internal

Client

SAF Advertisement

= SAF Client Protocol (SAF-CP)

= SAF Forwarder Protocol (SAF-FP)

= SAF Client Internal API

Legend:

SAFHeader

SAFService Data

AdjacentSAF Neighbors

Non-adjacent SAF Neighbors

Cisco IOS Router

Service SAF Service

The SAF Network

Service

SAFForwarder

& Internal Client running

SAF Service

SAF Service

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SAF Forwarder Protocol is a „Service‟ routing protocol

SAF-FP routes information about services over IP networks

SAF-FP is based on EIGRP and applies EIGRP capabilities to

distributing SAF Service information

Like EIGRP, SAF:

–Uses DUAL and Split Horizon to prevent loops

–Only sends updates when changes occur

–Is scalable and provides fast convergence

–Supports peer authentication to prevent malicious services

SAF can run with ANY IP routing protocol – RIP, EIGRP, OSPF, or

IS-IS can be used in the network

Non-SAF Cloud

SAF Forwarder Protocol - SAF-FP

SAFForwarder

SAFForwarder



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Dynamic Discovery – L2 Adjacent

Multicast

Occurs automatically on all enabled interfaces

Static Configuration – L2 Adjacent

Unicast

Prevents dynamic discovery on the same interface

Not configured

SAF Forwarder Neighbor Discovery

Dark Net

Static Configuration – Non-Adjacent

Unicast

Configured between each pair of forwarders

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SAF Forwarders can leverage Message Digest 5 (MD5) for authentication

MD5 prevents bogus Forwarders and Services from engaging in the SAF Network

External SAF Client(s) & SAF Forwarder(s) authentication is based on a Shared Secret

The Shared Secret consists of a username, password and random key that is computed locally by each device

Authentication not necessary for internal IOS SAF Client

SAF

Forwarder

SAF

External

Client

SAF

Forwarder

MD5

Authentication

Shared

Secret

SAF & Security

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The SAF Client-Network Interface

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SAF Clients perform three functions:

1. Register to the network

2. Publish services

3. Subscribe to services

External Clients communicate to a SAF Forwarder via the SAF Client Protocol (SAF-CP)

Internal Cisco IOS Clients communicate to a co-located SAF Forwarder via Internal API

(Cisco Unified CM) (CUCME, SRST, CUBE...)

SAF-CP

SAF Network

InternalAPI

ExternalClients

InternalIOS Clients

SAF-FP

SAF-FP

SAF Client Types

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Client must know IP address of the SAF Forwarder

Security - digest authentication based on Shared Secret

Once Client is authenticated it sends a register message to the Forwarder

Client uses unique „client label‟ to identify itself

Registered Client can publish or subscribe to SAF Network services

SAF Forwarder advertises all services published by the Cisco SAF Client

SAF Client sends Forwarder subscription requests for the services that it is interested in receiving

SAF Client uses the SAF-CP for Client registration, Client advertisements, and Client subscriptions

SAF Client Protocol – SAF-CP

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SAF Services –Call Control Discovery (CCD)

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IP Network

Call Agent

Call Agent

Call Agent GK

Existing call control approaches are limited

Configuration complexity - speed of deployment

High Operational Costs – TCO (Total Cost of Ownership)

Gatekeeper

Full Mesh of Dial Peers Centralized (Hub & Spoke) Dial Peers

Unified Communications Today

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Call Agent

Call AgentCall Agent

Call Agent

Call Agent

Call Agent

Call Agent

Call Agent Call Agent

Call Agent

Call Agent

Call Agent

Call Agent

Call Agent

Advert

ise

Consum

e

Service Type:Unified Communications

Sub-Service:Call Control Discovery

UC CCD is the first Cisco service that

leverages SAF

Call agents discover each other

through the SAF network by:

1. Advertising their CCD service

2. Requesting CCD services

Call agents dynamically route calls to

remote destinations based on learned

CCD services

Using SAF and Call Control Discovery:

–DN ranges operationally simplified

–Call control changes automatically distributed

–Seamless Moves / Adds / Changes

–Virtual mesh, best redundancy

–Full mesh complexity reduced

SAF Network

UC With SAF – Call Control Discovery

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Enables call agents to exchange dial plans, signaling protocols, and reachability information through SAF

CCD uses SAF to distribute information about the availability of internal DNs to other UC call agents

CCD leverages information learned from SAF to dynamically create dial plans for call control between call agents

SAF simplifies failover to the PSTN in case of an IP network outage

Call Manager, CME, CUBE and IOS Gateways can advertise CCD services, request CCD services, or both

UC CCD applications supported by SAF:

1. Advertising DN ranges 4. Automatic PSTN failover

2. Learning DN ranges 5. Automatic re-routing for SRST

3. Dynamic Call Routing 6. Legacy PBX integration

Call Control Discovery (CCD)

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New York

DN Pattern “to DID” rule IP address Protocol

8408XXXX 4:+1408555 10.1.1.1 SIP

8415XXXX 4:+1415777 10.1.1.1 SIP

8949XXXX 4:+1949222 10.1.1.1 SIP

New York CME Routing Table

San Jose

San Francisco Irvine

SAF-enabledIP Network

PSTN

8408XXXX

8415XXXX 8949XXXX

8212XXXX

10.1.1.110.2.2.2

IP address: 10.1.1.1

Protocol: SIP

DN Patterns:

8408XXXX [4:+1408555],

8415XXXX [4:+1415777],

8949XXXX [4:+1949222]

Service Advertisement

CCD – (1) Advertising DN Ranges

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New York


8212XXXX 4:+1212444 10.2.2.2 SIP

San Jose CUCM Routing Table

San Jose



PSTN

8408XXXX

8415XXXX 8949XXXX

8212XXXX

10.2.2.210.1.1.1


Protocol: SIP

DN Patterns:

8212XXXX [4:+1212444]

Service Advertisement

CCD – (2) Learning DN Ranges

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London

8442XXXX

10.3.3.3


8408XXXX +1408555 /4 10.1.1.1 SIP

8415XXXX +1415777 /4 10.1.1.1 SIP

8949XXXX +1949222 /4 10.1.1.1 SIP


8212XXXX +1212444 /4 10.2.2.2 SIP

New York



San Jose



PSTN

8408XXXX

8415XXXX 8949XXXX

8212XXXX

10.2.2.210.1.1.1

Call 84421000


8212XXXX 4:+1212444 10.2.2.2 SIP

8442XXXX 4:+442077111 10.3.3.3 H.323


8408XXXX 4:+1408555 10.1.1.1 SIP

8415XXXX 4:+1415777 10.1.1.1 SIP

8949XXXX 4:+1949222 10.1.1.1 SIP

8442XXXX 4:+442077111 10.3.3.3 H.323

CCD – (3) Dynamic Call Routing

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New York


8212XXXX 4:+1212444 10.2.2.2 SIP

8442XXXX 4:+442077111 10.3.3.3 H.323

San Jose CUCM Routing TableDN Pattern “to DID” rule IP address Protocol

8408XXXX 4:+1408555 10.1.1.1 SIP

8415XXXX 4:+1415777 10.1.1.1 SIP

8949XXXX 4:+1949222 10.1.1.1 SIP

8442XXXX 4:+442077111 10.3.3.3 H.323


San Jose



London

PSTN

8408XXXX

8415XXXX 8949XXXX8442XXXX

8212XXXX

10.2.2.2

10.3.3.3

10.1.1.1

8442XXXX

8442XXXX

Call 84421000

Translate to+4420771111000

CCD – (4) Automatic PSTN Failover

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New York


8408XXXX 4:+1408555 10.1.1.1 SIP

8415XXXX 4:+1415777 10.1.1.1 SIP

8949XXXX 4:+1949222 10.1.1.1 SIP

New York SRST Routing Table

San Jose



PSTN

8408XXXX

8415XXXX 8949XXXX

8212XXXX

10.1.1.110.2.2.2

Call 89491000

New York SRST subscribes to CCD service but does not publish any patterns

During WAN failures, SRST uses learned patterns to transparently re-route calls over the PSTN

CCD – (5) Automatic Re-Routing for SRST

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London

8442XXXX

10.3.3.3

Chicago


Chicago CUBE

Routing Table

San Jose



PSTN

8408XXXX

8415XXXX 8949XXXX

8312XXXX

10.4.4.410.1.1.1


8408XXXX 4:+1408555 10.1.1.1 SIP

8415XXXX 4:+1415777 10.1.1.1 SIP

8949XXXX 4:+1949222 10.1.1.1 SIP

8442XXXX 4:+442077111 10.3.3.3 H.323DN Pattern “to DID” rule IP address Protocol

8442XXXX 4:+442077111 10.3.3.3 H.323

8312XXXX 4:+1312888 10.4.4.4 SIP

3rd Party

IP PBX

Call 84156789

10.4.4.8CUBE


Protocol: SIP

DN Patterns:

8312XXXX [4:+1312888]

Static dial peerfor destination

8312XXXX

CCD – (6a) Legacy PBX – CUBE

35

London

8442XXXX

10.3.3.3

Boston

San Jose CUCM Routing Table Boston Gateway Routing Table

San Jose



PSTN

8408XXXX

8415XXXX 8949XXXX

8617XXX

10.5.5.510.1.1.1


8408XXXX 4:+1408555 10.1.1.1 SIP

8415XXXX 4:+1415777 10.1.1.1 SIP

8949XXXX 4:+1949222 10.1.1.1 SIP

8442XXXX 4:+442077111 10.3.3.3 H.323


8442XXXX 4:+442077111 10.3.3.3 H.323

8617XXXX 4:+1617999 10.5.5.5 SIP

3rd Party

TDM PBX

TDM

Call 84156789

Cisco IOSGateway

Static dial peerfor destination

8617XXXX

CCD – (6b) Legacy PBX – IOS Gateway

36

Call Control Discovery Benefits

Reduce deployment time, realize quicker ROI

– Dial plan configuration complexity all but eliminated

– Allows optimal dial plan to be implemented quickly (on-net numbering plan with automatic PSTN failover)

Reduce ongoing operational costs

– Complexity of adding/removing/changing a site drastically reduced

– CCD automatically advertises changes in the UC network

Improve business continuity

– Increased availability even during partial network failure thanks to dynamic update awareness via SAF Advertisements

– Fast call rerouting during failures

37

SAF Deployment and Configuration

38

CiscoUnified CM

CiscoUnified CM

CUBE

Cisco

IOS GW

CUCMESRST

CCD CCD

SAFForwarder

SAFClient

SAF-unawareRouter

SAF-CP SAF-CP

CCD CCD CCD

Internal API Internal API

SAF Network, Client-Network Interface, SAF Service


SAFForwarder


39

1. Enable SAF on Transitive Forwarder for Layer 2 adjacencies

2. Enable SAF on Transitive Forwarder with static neighbor relationships – Non-Adjacent

3. Configuring Route Authentication between SAF Forwarders

4. Configuring Forwarder to support external SAF Clients

5. Enable SAF on Clients (not covered)

SAF Configuration Steps

40

Forwarder_1#config t

Forwarder_1(config)#router eigrp saf

Forwarder_1(config-router)#service-

family ipv4 autonomous-system 1

Forwarder_1(config-router-sf)#sf-

interface default


interface Ethernet0/0 (optional)

Step #1 – execute the ‘router eigrp’ command, then use ‘service-family’






interface default


interface Ethernet0/0 (optional)

SAF Forwarder 1 SAF Forwarder 2

Enable SAF on Forwarder – Layer 2 Adjacent

Eth0/0 Eth0/1

Forwarder 1 Forwarder 2

L2 Adjacent

41


Forwarder_3(config)#interface

Loopback0

Forwarder_3(config-if)#ip address

10.10.0.1 255.255.255.0




Forwarder_3(config-router-sf)#

neighbor 10.20.0.1 loopback0 remote 3

Step #2 – execute the ‘router eigrp’ command, ‘service-family’, & ‘neighbor’


Forwarder_4(config)#interface

Loopback0

Forwarder_4(config-if)#ip address

10.20.0.1 255.255.255.0




Forwarder_4(config-router-sf)#

neighbor 10.10.0.1 loopback0 remote 3

SAF Forwarder 3 SAF Forwarder 4

Enable SAF on Forwarder – Static Neighbor, Non-Adjacent

Loop0

10.10.0.1

Loop0

10.20.0.1

Dark NetForwarder 3 Forwarder 4

Non-Adjacent

42



Forwarder_1(config-router)#service-family ipv4 autonomous-system 1

Forwarder_1(config-router-sf)#sf-interface loopback 0

Forwarder_1(config-router-sf-interface)#authentication key-chain EXAMPLE

Forwarder_1(config-router-sf-interface)#authentication mode md5

Forwarder_1(config-router-sf-interface)#exit-sf-interface

Forwarder_1(config-router-sf)#exit-service-family

Forwarder_1(config-router)#

Forwarder_1(config-router)#exit

Forwarder_1(config)#key chain EXAMPLE

Forwarder_1(config-keychain)#key 0

Forwarder_1(config-keychain-key)#key-string EXAMPLE

Forwarder_1(config-keychain-key)#accept-lifetime 12:00:00 1 JAN 2010 infinite

Forwarder_1(config-keychain-key)#send-lifetime 12:00:00 1 JAN 2010 infinite

Step #3 – execute the ‘authentication key-chain command’

Configuring Route Authentication for SAF

SAF Forwarder 1 MD5 Auth

43



Forwarder_1(config-router)#service-family ipv4 autonomous-system 1

Forwarder_1(config-router-sf)#topology base

Forwarder_1(config-router-topology)#external-client SAF-CLIENT

Forwarder_1(config-router-sf-topology)#exit-sf-topology

Forwarder_1(config-router-sf)#exit-service-family

Forwarder_1(config-router)#exit

Forwarder_1(config)#service-family external-client listen ipv4 5050

Forwarder_1(config-external-client)#external-client SAF-CLIENT basename

Forwarder_1(config-external-client-mode)#username SAF-CLIENT

Forwarder_1(config-external-client-mode)#password SAF-CLIENT_PASSWORD

Step #4 – execute the ‘external client’ & ‘service-family external client’ command

Forwarder Config to Support External SAF Clients

SAF Forwarder 1

Shared

Secret

44


45

FEATURES BENEFITS

Provides a framework that allows networking applications to automatically discover networked services within networks

Reduce deployment time, realize

quicker ROI

Allows user to create a configuration

once, and then have it propagate to

all devices that require the

information

Reduce ongoing operational costs

Automated discovery and

advertising of services replaces the

manual entry of complex

configurations

Improve business continuity

Supports Non-SAF nodes SAF Forwarders can communicate over any IP network, SAF does not need to be enabled on every device


46

SAF Summary

47

SAF is a generic framework for service discovery

Three main components:

– The Network – propagate service advertisements

– The Client-Network Interface – publish and subscribe to services

– SAF Services – e.g., Call Control Discovery

SAF roles include: SAF Forwarder, SAF Client, SAF Service, SAF Advertisement, and Non-SAF Node

SAF-FP is between Forwarders, SAF-CP is between Forwarder and an external Client

Call Control Discovery enables call agents to exchange dial plans, signaling protocols, and reachability information through SAF

UC CCD Applications Supported by SAF: Advertising DN Ranges, Learning DN Ranges, Dynamic Call Routing, Automatic PSTN Failover, Automatic Rerouting for SRST, Legacy PBX Integration –CUBE and Gateway

Benefits of SAF include: reduced deployment times, reduced ongoing operational costs, and improved business continuity

SAF Summary

49

SAF Q and A http://www.cisco.com/en/US/prod/collateral/iosswrel/ps6537/ps6554/ps6599/ps10822/qa_c67-573463.html

SAF Introduction and Resources http://www.cisco.com/en/US/products/ps10822/products_ios_protocol_option_home.html

SAF Whitepaper http://www.cisco.com/en/US/prod/collateral/iosswrel/ps6537/ps6554/ps6599/ps10822/whitepaper_c11-573461.html

SAF Configuration Guide http://www.cisco.com/en/US/docs/ios/saf/configuration/guide/saf_cg_ps10592_TSD_Products_Configuration_Guide_Chapter.html

SAF Resources

http://www.cisco.com/en/US/prod/collateral/iosswrel/ps6537/ps6554/ps6599/ps10822/qa_c67-573463.html




http://www.cisco.com/en/US/products/ps10822/products_ios_protocol_option_home.html

http://www.cisco.com/en/US/products/ps10822/products_ios_protocol_option_home.html

http://www.cisco.com/en/US/prod/collateral/iosswrel/ps6537/ps6554/ps6599/ps10822/whitepaper_c11-573461.html




http://www.cisco.com/en/US/docs/ios/saf/configuration/guide/saf_cg_ps10592_TSD_Products_Configuration_Guide_Chapter.html



service advertisement framework

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