Inter-domain AMT Multicast

Use Case Discussion

Proposal for AMT MulticastSource-AMT Connectivity Model For

Inter-connected Networks (AS’s)

1

Problem With the existing model for AMT anycast addressing, when an end-user requests multicast content via AMT,

the request will be routed to the nearest AMT Relay, which could be in the requestor’s local network or any other network.

For the connection to be successful, the end-user must reach an AMT Relay that has multicast connectivity to the Multicast Source that originates the content.

If the AMT Relay reached by the end-user does not have multicast connectivity to the source, the result will be a failure to obtain the content via multicast.

If the AMT Relay reached does have multicast connectivity with the source, but is located in a distant network, in many cases the following highly inefficient AMT tunnel will result.

Anycast Addressing Issue

AMT Relay

Internet

Multicast Source

Multicast-enabled

Source Network End-User’s Network

AMTGateway

A way is needed to route an anycast AMT request to the closest AMT Relay that has multicast connectivity to the requested Source. This could be a local (to the end-user) AMT Relay on another provider’s network, or an AMT Relay in the Multicast Source’s network, or an AMT Relay in an intermediate network.

2

© 2011 AT&T Intellectual Property. All rights reserved.

Network 2

AMT Relay 2

Network 1

AMT Relay 1Multicast Source 1

Network 7

LocalDNS 7

Network 8

LocalDNS 8

Network 3

AMT Relay 3

Network 4

AMT Relay 4AMTDNS 4

Network 6

AMT Relay 6AMTDNS 6

Network 5

AMT Relay 5AMTDNS 5

Federation A Federation B

Network Architecture and Connectivity

AMTDNS 2

AMTDNS 1

AMTDNS 3

3

Multicast-enabled interconnection

Unicast-only interconnection

Federation A Federation Band networks are internally multicast-enabled

Networks 7 and 8 are not multicast-enabled

Author.DNS 1

Author.DNS 2

Author.DNS 3

Author.DNS 4

Author.DNS 5

Author.DNS 6

Requirements for Solution

Only three requirements:

1. In a network that hosts a Multicast Source, the Authoritative DNS server has an “in-addr.arpa” address entry for the Source IP.

• E.g., for S1 of (S1,G1) = 1.x.y.z, there is an entry in Authoritative DNS 1 for “z.y.x.1.in-addr.arpa” that maps to the anycast address described in #2 below.

2. All networks (members of the same “Federation”) that have multicast connectivity to S1 and wish to server content from that Source, must have “AMT DNS” servers reachable by the same anycast address, and the entries in those AMT DNS servers map to the AMT Relays in their own networks.

• E.g., AMT DNS 1, AMT DNS 2, and AMT DNS 3 in the diagrams are reachable by the same anycast address, and they have entries that map to the address of their own network’s AMT Relays. So, AMT DNS 1 maps queries to AMT Relay(s) 1, AMT DNS 2 maps to AMT Relay(s) 2, AMT DNS 3 maps to AMT Relay(s) 3.

3. AMT Gateways seek to find an AMT Relay by the deterministic construction of an “in-addr.arpa” DNS query* of the form

“z.y.x.A.in-addr.arpa”

Where “A” is (e.g.) the class A address allocated to the Source’s host network, and “A.x.y.z” is the IP address of the Source specified in the (S,G).

4

* Instead of using the global AMT anycast address

Network 2

AMT Relay 2

Network 1

AMT Relay 1Multicast Source 1

Network 7

LocalDNS 7

Network 8

LocalDNS 8

Network 3

AMT Relay 3

Network 4

AMT Relay 4AMTDNS 4

Network 6

AMT Relay 6AMTDNS 6

Network 5

AMT Relay 5AMTDNS 5

AMTGateway

1 “z.y.x.1.in-addr.arpa”

End-user application on Network 8 wants content on S1 (1.x.y.z), the AMT Gateway determines it does not have native multicastaccess to S1, seeks to connect via AMT Relay, constructs DNS query for “z.y.x.1.in-addr.arpa”

AMTDNS 2

AMTDNS 1

AMTDNS 3

5

Federation A Federation B

Author.DNS 1

Author.DNS 2

Author.DNS 3

Author.DNS 4

Author.DNS 5

Author.DNS 6

Network 2

AMT Relay 2

Network 1

AMT Relay 1Multicast Source 1

Network 7

LocalDNS 7

Network 8

LocalDNS 8

Network 3

AMT Relay 3

Network 4

AMT Relay 4AMTDNS 4

Network 6

AMT Relay 6AMTDNS 6

Network 5

AMT Relay 5AMTDNS 5

AMTGateway

2 “z.y.x.1.in-addr.arpa”

Network 8 Local DNS performs recursive queries,eventually finds Authoritative DNS 1

AMTDNS 2

AMTDNS 1

AMTDNS 3

6

Federation A Federation B

Author.DNS 1

Author.DNS 2

Author.DNS 3

Author.DNS 4

Author.DNS 5

Author.DNS 6

Network 2

AMT Relay 2

Network 1

AMT Relay 1Multicast Source 1

Network 7

LocalDNS 7

Network 8

LocalDNS 8

Network 3

AMT Relay 3

Network 4

AMT Relay 4AMTDNS 4

Network 6

AMT Relay 6AMTDNS 6

Network 5

AMT Relay 5AMTDNS 5

AMTGateway

3 “a.b.c.d” Anycast

Network 1 Authoritative DNS redirects query to “a.b.c.d”,the anycast address for all Federation A“AMT DNS” servers (AMT DNS 1, 2, & 3)

AMTDNS 2

AMTDNS 1

AMTDNS 3

7

Federation A Federation B

Author.DNS 1

Author.DNS 2

Author.DNS 3

Author.DNS 4

Author.DNS 5

Author.DNS 6

Network 2

AMT Relay 2

Network 1

AMT Relay 1Multicast Source 1

Network 7

LocalDNS 7

Network 8

LocalDNS 8

Network 3

AMT Relay 3

Network 4

AMT Relay 4AMTDNS 4

Network 6

AMT Relay 6AMTDNS 6

Network 5

AMT Relay 5AMTDNS 5

AMTGateway

4 Send query for “z.y.x.1.in-addr.arpa”to DNS server at “a.b.c.d” Anycast IP

Network 8 Local DNS sends a query for “z.y.x.1.in-addr.arpa” to “a.b.c.d”, the anycast address for all Federation A“AMT DNS” servers, which is naturally routed toAMT DNS 3, the closest AMT DNS serverin Federation A

AMTDNS 2

AMTDNS 1

AMTDNS 3

8

Federation A Federation B

Author.DNS 1

Author.DNS 2

Author.DNS 3

Author.DNS 4

Author.DNS 5

Author.DNS 6

Network 2

AMT Relay 2

Network 1

AMT Relay 1Multicast Source 1

Network 7

LocalDNS 7

Network 8

LocalDNS 8

Network 3

AMT Relay 3

Network 4

AMT Relay 4AMTDNS 4

Network 6

AMT Relay 6AMTDNS 6

Network 5

AMT Relay 5AMTDNS 5

AMTGateway

5 AMT Relay 3 IP Address

Entries in Network 3 AMT DNS map to Network 3’s own AMT Relays because Network 3 has multicastconnectivity to S1, thus AMT DNS 3 returnsIP address of AMT Relay 3

AMTDNS 2

AMTDNS 1

AMTDNS 3

9

Federation A Federation B

Author.DNS 1

Author.DNS 2

Author.DNS 3

Author.DNS 4

Author.DNS 5

Author.DNS 6

Network 2

AMT Relay 2

Network 1

AMT Relay 1Multicast Source 1

Network 7

LocalDNS 7

Network 8

LocalDNS 8

Network 3

AMT Relay 3

Network 4

AMT Relay 4AMTDNS 4

Network 6

AMT Relay 6AMTDNS 6

Network 5

AMT Relay 5AMTDNS 5

AMTGateway

6 AMT Relay 3 IP Address

End-user receives IP address of optimal AMT Relay for S1

AMTDNS 2

AMTDNS 1

AMTDNS 3

10

Federation A Federation B

Author.DNS 1

Author.DNS 2

Author.DNS 3

Author.DNS 4

Author.DNS 5

Author.DNS 6

Network 2

AMT Relay 2

Network 1

AMT Relay 1Multicast Source 1

Network 7

LocalDNS 7

Network 8

LocalDNS 8

Network 3

AMT Relay 3

Network 4

AMT Relay 4AMTDNS 4

Network 6

AMT Relay 6AMTDNS 6

Network 5

AMT Relay 5AMTDNS 5

AMTGateway

End-user GW establishes optimal tunnel for content at S1

Multicast

AMT TunnelAMT

DNS 2

AMTDNS 1

AMTDNS 3

11

Federation A Federation B

Author.DNS 1

Author.DNS 2

Author.DNS 3

Author.DNS 4

Author.DNS 5

Author.DNS 6

Network 2

AMT Relay 2

AMT Relay 1Multicast Source 1

Network 7

LocalDNS 7

Network 8

LocalDNS 8

Network 3

AMT Relay 3

Network 4

AMT Relay 4

Network 6

AMT Relay 6

Network 5

AMT Relay 5

AMTDNS 2

AMTDNS 1

AMTDNS 3

AMTDNS 5

AMTDNS 4

AMTDNS 6

Multicast Source 5

Network Architecture and Connectivity – End-user Wants Content at Multicast Source 5

12

Federation A Federation B

Network 1

Author.DNS 1

Author.DNS 2

Author.DNS 3

Author.DNS 4

Author.DNS 5

Author.DNS 6

Network 2

AMT Relay 2

Network 1

AMT Relay 1Multicast Source 1

Network 7

LocalDNS 7

Network 8

LocalDNS 8

Network 3

AMT Relay 3

Network 4

AMT Relay 4

Network 6

AMT Relay 6

Network 5

AMT Relay 5

AMTGateway

1 “z.y.x.5.in-addr.arpa”

End-user Gateway determines no native multicast accessto S5 (IP address = “5.x.y.z”), seeks to connect via AMT Relay,queries DNS to resolve “z.y.x.5.in-addr.arpa”

Multicast Source 5

AMTDNS 5

AMTDNS 4

AMTDNS 6

AMTDNS 2

AMTDNS 1

AMTDNS 3

13

Federation A Federation B

Author.DNS 1

Author.DNS 2

Author.DNS 3

Author.DNS 4

Author.DNS 5

Author.DNS 6

Network 2

AMT Relay 2

Network 1

AMT Relay 1Multicast Source 1

Network 7

LocalDNS 7

Network 8

LocalDNS 8

Network 3

AMT Relay 3

Network 4

AMT Relay 4

Network 6

AMT Relay 6

Network 5

AMT Relay 5

AMTGateway

2 “z.y.x.5.in-addr.arpa”

Network 8 local DNS performs recursive queries,finds Authoritative DNS 5

Multicast Source 5

AMTDNS 5

AMTDNS 4

AMTDNS 6

AMTDNS 2

AMTDNS 1

AMTDNS 3

14

Federation A Federation B

Author.DNS 1

Author.DNS 2

Author.DNS 3

Author.DNS 4

Author.DNS 5

Author.DNS 6

Network 2

AMT Relay 2

Network 1

AMT Relay 1Multicast Source 1

Network 7

LocalDNS 7

Network 8

LocalDNS 8

Network 3

AMT Relay 3

Network 4

AMT Relay 4

Network 6

AMT Relay 6

Network 5

AMT Relay 5

AMTGateway

3 “e.f.g.h” Anycast

Authoritative DNS 5 redirects query to “e.f.g.h”,the Anycast address for all Federation B“AMT DNS” servers (AMT DNS 4, 5, & 6)

Multicast Source 5

AMTDNS 5

AMTDNS 4

AMTDNS 6

AMTDNS 2

AMTDNS 1

AMTDNS 3

15

Federation A Federation B

Author.DNS 1

Author.DNS 2

Author.DNS 3

Author.DNS 4

Author.DNS 5

Author.DNS 6

Network 2

AMT Relay 2

Network 1

AMT Relay 1Multicast Source 1

Network 7

LocalDNS 7

Network 8

LocalDNS 8

Network 3

AMT Relay 3

Network 4

AMT Relay 4AMTDNS 4

Network 6

AMT Relay 6AMTDNS 6

Network 5

AMT Relay 5AMTDNS 5

AMTGateway

4 Send query for “z.y.x.5.in-addr.arpa”to DNS server at “e.f.g.h” Anycast IP

Network 8 Local DNS sends a query for “z.y.x.5.in-addr.arpa” to “e.f.g.h”, the anycast address for Federation B “AMT DNS” servers, which is naturally routed to AMT DNS 6,the closest AMT DNS server in Federation B

AMTDNS 2

AMTDNS 1

AMTDNS 3

16

Federation A Federation B

Author.DNS 1

Author.DNS 2

Author.DNS 3

Author.DNS 4

Author.DNS 5

Author.DNS 6

Network 2

AMT Relay 2

Network 1

AMT Relay 1Multicast Source 1

Network 7

LocalDNS 7

Network 8

LocalDNS 8

Network 3

AMT Relay 3

Network 4

AMT Relay 4AMTDNS 4

Network 6

AMT Relay 6AMTDNS 6

Network 5

AMT Relay 5AMTDNS 5

AMTGateway

5 AMT Relay 6 IP Address

Entries in Network 6 AMT DNS map to Network 6’s own AMT Relays because Network 6 has multicastconnectivity to S5, thus AMT DNS 6 returnsIP address of AMT Relay 6

AMTDNS 2

AMTDNS 1

AMTDNS 3

17

Federation A Federation B

Author.DNS 1

Author.DNS 2

Author.DNS 3

Author.DNS 4

Author.DNS 5

Author.DNS 6

Network 2

AMT Relay 2

Network 1

AMT Relay 1Multicast Source 1

Network 7

LocalDNS 7

Network 8

LocalDNS 8

Network 3

AMT Relay 3

Network 4

AMT Relay 4AMTDNS 4

Network 6

AMT Relay 6AMTDNS 6

Network 5

AMT Relay 5AMTDNS 5

AMTGateway

6 AMT Relay 6 IP Address

End-user receives IP address of optimal AMT Relay for S5

AMTDNS 2

AMTDNS 1

AMTDNS 3

18

Federation A Federation B

Author.DNS 1

Author.DNS 2

Author.DNS 3

Author.DNS 4

Author.DNS 5

Author.DNS 6

© 2011 AT&T Intellectual Property. All rights reserved.

Network 2

AMT Relay 2

Network 1

AMT Relay 1Multicast Source 1

Network 7

LocalDNS 7

Network 8

LocalDNS 8

Network 3

AMT Relay 3

Network 4

AMT Relay 4

Network 6

AMT Relay 6

Network 5

AMT Relay 5

AMTGateway

End-user GW establishes optimal tunnel for content at S5

Multicast

AMT TunnelAMT

DNS 2

AMTDNS 1

AMTDNS 3

Multicast Source 5

AMTDNS 5

AMTDNS 4

AMTDNS 6

19

Federation A Federation B

Author.DNS 1

Author.DNS 2

Author.DNS 3

Author.DNS 4

Author.DNS 5

Author.DNS 6