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This chapter is from the book

Implementing URD Host Signaling

The following sections describe how an ISP customer within an interdomain multicast network implemented SSM in its network using URD. This section covers the following topics:

  • Prerequisite

  • Implementation Process Steps

Prerequisite

The prerequisite for deploying SSM using URD is to configure interdomain multicast using the following configuration tasks:

  • Configure MBGP to exchange multicast routing information.

  • Configure multicast borders appropriately.

For more information on how to perform these configuration tasks, refer to Chapter 2.

Implementation Process Steps

The following steps were used to configure SSM using URD on the devices shown in Figure 6-2. For more information about the commands used to configure SSM using URD, please refer to Appendix A, "IP Multicast Command Summary." For more information about how each device in the ISP was configured, please refer to Chapter 7, "Device Characteristics and Configuration Files for Implementing Interdomain Multicast Using SSM."

The multicast solutions in this document were tested with valid IP addresses. Normally, when a configuration file is published, the valid IP addresses are replaced with IP addresses specified in RFC 1918, "Address Allocation for Private Networks." Because the range of available IP addresses was insufficient to span the range of IP addresses used in this solution, the first octet of the valid IP addresses was replaced with a variable. In the example configurations provided in the following sections, the first octet of these reserved IP addresses has been replaced with the letter J or the letter K for privacy reasons. The letter J always represents one unique number, and the letter K always represents a unique number that is different from J.

The example configurations are intended for illustrative purposes only. The letters J and K must be replaced with valid numbers when these IP addresses are configured in an actual network.

NOTE

The example configurations provided in the following sections use highlighted text to indicate pertinent configuration commands used for deploying the IP multicast solutions described in this document.

Use the following steps to configure SSM using URD on the devices shown in Figure 6-2:

Step 1 Select and enable the SSM range in the ISP.

The following sample configuration shows how to select and enable the SSM range in ISP1:

ip pim ssm

Step 2 Configure filters on the RP for PIM-SM and MSDP traffic in the SSM address range.

The following sample configuration shows how to configure filters on the RP (ISP1BB3 router) for PIM-SM and MSDP traffic in the SSM address range:

ip msdp sa-filter in J.4.0.203 list 124
ip msdp sa-filter out J.4.0.203 list 124

The following access list is configured on the ISP1BB3 router:

access-list 124 deny   ip any host 224.0.2.2
access-list 124 deny   ip any host 224.0.1.3
access-list 124 deny   ip any host 224.0.1.24
access-list 124 deny   ip any host 224.0.1.22
access-list 124 deny   ip any host 224.0.1.2
access-list 124 deny   ip any host 224.0.1.35
access-list 124 deny   ip any host 224.0.1.60
access-list 124 deny   ip any host 224.0.1.39
access-list 124 deny   ip any host 224.0.1.40
access-list 124 deny   ip any 239.0.0.0 0.255.255.255
access-list 124 deny   ip 10.0.0.0 0.255.255.255 any
access-list 124 deny   ip 127.0.0.0 0.255.255.255 any
access-list 124 deny   ip 172.16.0.0 0.15.255.255 any
access-list 124 deny   ip 192.168.0.0 0.0.255.255 any
access-list 124 deny   ip any 232.0.0.0 0.255.255.255

Step 3 Configure URD on user interfaces.

The following sample configuration shows how to configure URD on Ethernet5/3 on the ISP1AC1 router. The ip urd interface configuration command enables interception of TCP packets sent to the reserved URD port 465 on an interface and the processing of URD channel subscription reports.

ISP1AC1# configure terminal
Enter configuration commands, one per line.  End with CNTL/Z.
ISP1AC1(config)# interface Ethernet 5/3
ISP1AC1(config-if)# ip urd
ISP1AC1(config-if)#

Step 4 Verify that URD clients can connect to a source. (Optional)

(a) Enable debug output and attempt to connect to a source:

ISP1AC1# debug ip igmp 232.0.2.1
ISP1AC1# debug ip igmp 232.0.2.2
ISP1AC1# debug ip urd
ISP1AC1# debug ip mrouting

Mar 7 14:17:37 PST:URD:Intercepted TCP SYN packet from K.250.1.41, 0:772431754(ack:seq)
Mar 7 14:17:37 PST:URD:Intercepted TCP ACK packet from K.250.1.41, 48154099:772431755(ack:seq)
Mar 7 14:17:37 PST:URD:Data intercepted from K.250.1.41, offset 5
Mar 7 14:17:37 PST:URD:Enqueued string:'/cgi-bin/error.html
              ?group=232.0.2.2&port=22306&source=J.2.11.6&lifet'
Mar 7 14:17:37 PST:URD:Dequeued URD packet, len:137
Mar 7 14:17:37 PST:URD:String:/cgi-bin/error.html
              ?group=232.0.2.2&port=22306&source=J.2.11.6&lifetim e=7200
              &group=232.0.2.1&port=49254&source=J.2.11.6&lifetime=7200
Mar 7 14:17:37 PST:URD:Matched token:group
Mar 7 14:17:37 PST:URD:Parsed value:232.0.2.2
Mar 7 14:17:37 PST:URD:Matched token:source
Mar 7 14:17:37 PST:URD:Parsed value:J.2.11.6
Mar 7 14:17:37 PST:URD:Matched token:lifetime
Mar 7 14:17:37 PST:URD:Parsed value:7200
Mar 7 14:17:37 PST:URD:Matched token:group
Mar 7 14:17:37 PST:URD:Parsed value:232.0.2.1
Mar 7 14:17:37 PST:URD:Matched token:source
Mar 7 14:17:37 PST:URD:Parsed value:J.2.11.6
Mar 7 14:17:37 PST:URD:Matched token:lifetime
Mar 7 14:17:37 PST:URD:Parsed value:7200

Mar 7 14:17:37 PST:URD:Creating IGMP source state for group 232.0.2.2
Mar 7 14:17:37 PST:IGMP:Setting source flags 18 on (J.2.11.6,232.0.2.2)

Mar 7 14:17:37 PST:URD:Creating IGMP source state for group 232.0.2.1
Mar 7 14:17:38 PST:MRT:Create (J.2.11.6/32, 232.0.2.1), RPF 
  FastEthernet3/0/K.250.1.1, PC 0x609E5CA0
Mar 7 14:17:38 PST:MRT:Add/Update Ethernet5/3/232.0.2.1 to the olist of 
  (J.2.11.6, 232.0.2.1), Forward state
Mar 7 14:17:38 PST:MRT:Create (K.250.1.41/32, 232.0.2.1), RPF 
  Ethernet5/3/0.0.0.0, PC 0x609F25FC

Mar 7 14:17:39 PST:IGMP:Received v2 Report on Ethernet5/3 from 
  K.250.1.41 for 232.0.2.2
Mar 7 14:17:39 PST:MRT:Create (J.2.11.6/32, 232.0.2.2), RPF 
  FastEthernet3/0/K.250.1.1, PC 0x609E5CA0
Mar 7 14:17:39 PST:MRT:Add/Update Ethernet5/3/232.0.2.2 to the olist of 
  (J.2.11.6, 232.0.2.2), Forward state
Mar 7 14:17:39 PST:MRT:Create (K.250.1.41/32, 232.0.2.2), RPF 
  Ethernet5/3/0.0.0.0, PC 0x609F25FC
(b)	Verify that SSM flags are set:
ISP1AC1# show ip mroute

IP Multicast Routing Table
Flags:D - Dense, S - Sparse, B - Bidir Group, s - SSM Group, C - Connected,
       L - Local, P - Pruned, R - RP-bit set, F - Register flag,
       T - SPT-bit set, J - Join SPT, M - MSDP created entry,
       X - Proxy Join Timer Running, A - Advertised via MSDP, U - URD,
       I - Received Source Specific Host Report
Outgoing interface flags:H - Hardware switched
Timers:Uptime/Expires
Interface state:Interface, Next-Hop or VCD, State/Mode

(*, 224.0.1.40), 00:01:55/00:00:00, RP K.250.0.201, flags:SJCL
  Incoming interface:Null, RPF nbr 0.0.0.0
  Outgoing interface list:
    Loopback0, Forward/Sparse, 00:01:55/00:02:59

(J.2.11.6, 232.0.2.2), 00:00:45/00:02:59, flags:sCTUI
  Incoming interface:FastEthernet3/0, RPF nbr K.250.1.1
  Outgoing interface list:
    Ethernet5/3, Forward/Sparse, 00:00:16/00:02:46

(K.250.1.41, 232.0.2.2), 00:00:45/00:02:14, flags:sPCT
  Incoming interface:Ethernet5/3, RPF nbr 0.0.0.0
  Outgoing interface list:Null
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