multicast address discovery protocol

1MulticastAddressLocationProtocol

Multicast AddressDiscovery Protocol

IETF Vancouver – Oct 2005

222MulticastAddressLocationProtocol

Problem

• Enterprise Networks wish to deploy Scoped Zones.– Allows them to limit the scope of applications.• Examples: Norton Ghost, Altiris

– Many applications use “fixed” addresses.• Often due to need for (near) zero-configuration operation.• Some haven’t even bothered to register with IANA!!Some haven’t even bothered to register with IANA!!– Address Assignment by “Atmospheric Extraction”.

– Scope range maintenance becomes complex• Must make exceptions for these “rogue” applications.• More and more such applications popping up.

– Need a way to achieve (near) zero-configuration and yet give network admin control of addresses used by apps.

333MulticastAddressLocationProtocol

RFC 2365LocalScope

RFC 2365Local ScopeExpansion

RFC 2365Org.-LocalExpansion

239.255.0.0

239.196.0.0

239.255.255.255

239.0.0.0

RFC 2365Org-Local

Scope

239.192.0.0

RFC 2365 – Administratively Scoped Zones

• Defines only 2 Well-Known Scopes–Organization-Local Scope (239.192/14)• Largest scope within the Enterprise

network.– Local Scope (239.255/16)• Smallest possible scope within the

Enterprise network.–Other scopes may be equal to but not

smaller in scope.–Both scopes have expansion space below

their range.

(Not to scale.)

Unassigned

239.255.253.0

444MulticastAddressLocationProtocol

Scope Relative Addresses – RFC 2365

LastOctet

Offset Description

.255 0 SAP Session Announcement Protocol (SDR)

.254 1 MADCAP Protocol

.253 2 SLPv2 Protocol

.252 3 MZAP Protocol

.251 4 Multicast Discovery of DNS Services

.250 5 SSDP

.249 6 DHCPv4

.248 7 AAP

.247 8 MBUS

9 - 255 Unassigned

Top 256 Addresses of every Admin. Scope Range.

555MulticastAddressLocationProtocol

Scope Relative – Local Scope

239.255.255.255

239.255.0.0

Local ScopeScope Relative

239.255.255.0

Local Scope

239.254.255.255

239.0.0.0

(Not to scale.)

Address Description239.255.255.255 SAP Session Announcement Protocol (SDR)239.255.255.254 MADCAP Protocol239.255.255.253 SLPv2 Protocol239.255.255.252 MZAP Protocol239.255.255.251 Multicast Discovery of DNS Services239.255.255.250 SSDP239.255.255.249 DHCPv4239.255.255.248 AAP239.255.255.247 MBUS

666MulticastAddressLocationProtocol

Scope Relative – Org-Local Scope

239.195.255.255

239.192.0.0

Org-Local Scope Relative

239.195.255.0

Org-Local Scope

239.195.254.255

239.0.0.0

(Not to scale.)

Address Description239.195.255.255 SAP Session Announcement Protocol (SDR)239.195.255.254 MADCAP Protocol239.195.255.253 SLPv2 Protocol239.195.255.252 MZAP Protocol239.195.255.251 Multicast Discovery of DNS Services239.195.255.250 SSDP239.195.255.249 DHCPv4239.195.255.248 AAP239.195.255.247 MBUS

777MulticastAddressLocationProtocol

Administratively-Scoped Zone Example

• ACME Enterprises:–Three levels of internal scopes •Campus Scope•Region Scope•Org-Local Scope– aka Enterprise-Wide Scope

–One external scope•Global scope• i.e. everything else (Internet)

888MulticastAddressLocationProtocol

ACME’s Scoped Zones

ASIAPAC North America

Core

EMEA

Canada East Coast US

West CoastUS

NorthRegion

EasternRegion

South Region

India

Japan

Australia

China

Internet

999MulticastAddressLocationProtocol

ACME’s Scoped Zones

ASIAPAC North America

Core

EMEA

Canada East Coast US

West CoastUS

NorthRegion

EasternRegion

South Region

India

Japan

Australia

China

Internet

• Campus Scope: 239.190.x.x/16

Campus Scope

101010MulticastAddressLocationProtocol

ACME’s Scoped Zones

ASIAPAC North America

Core

EMEA

Canada East Coast US

West CoastUS

NorthRegion

EasternRegion

South Region

India

Japan

Australia

China

Internet

• Regional Scope : 239.191.x.x/16

RP

RP

RP

Regional Scope

111111MulticastAddressLocationProtocol

ACME’s Scoped Zones

ASIAPAC North America

Core

EMEA

Canada East Coast US

West CoastUS

NorthRegion

EasternRegion

South Region

India

Japan

Australia

China

Internet

• Enterprise Scope: 239.192.x.x/14– i.e. Org-Local Scope

Enterprise Scope

121212MulticastAddressLocationProtocol

ACME’s Scoped Zones

ASIAPAC North America

Core

EMEA

Canada East Coast US

West CoastUS

NorthRegion

EasternRegion

South Region

India

Japan

Australia

China

Internet

• Global Scope: 224.0.1.x – 238.255.255.255

Global (Internet) Scope

131313MulticastAddressLocationProtocol

RFC 2365Organization-Local Scope

ACME’s Address Assignments

• Enterprise scope = RFC 2365 Org-Local• Keep Local scope separate.–Avoids moving applications when smaller

scopes are added later.• Lots of other ways to assign this space.

RFC 2365LocalScope

239.255.0.0

239.196.0.0

239.255.255.255

239.0.0.0

RegionScope (/16)

CampusScope (/16)

EnterpriseScope (/14)

239.192.0.0

239.191.0.0

239.190.0.0

141414MulticastAddressLocationProtocol

Solution

•Multicast Address Discovery Protocol–Very light-weight–Assumes no support infrastructure other than:• IP Multicast•RFC 2365 Administratively Scoped Zones– Well-Known Scopes (Local & Org. Local Scopes)– Scope Relative Addresses

–Runs entirely in Application Clients and Servers

151515MulticastAddressLocationProtocol

MADP Basics

• Uses a single Scope Relative Address• Clients send Queries on this address– Request info on what multicast address(es)

application “X” is using.– Initial Queries sent in the Local Scope.– If no response, then queries the Org-Local Scope.

• Servers listen on these addresses.– When a Request is received, they check to see if they are

the Server for application “X”.– If so, they send a Response containing multicast address

information.• Address information was preconfigured by network admin.