No relevant resource is found in the selected language.

This site uses cookies. By continuing to browse the site you are agreeing to our use of cookies. Read our privacy policy>Search


To have a better experience, please upgrade your IE browser.


Configuration Guide - IP Multicast

CloudEngine 12800 and 12800E V200R005C10

This document describes the configurations of IP multicast, including IP multicast basics, IGMP, MLD, PIM (IPv4), PIM (IPv6), MSDP, multicast VPN, multicast route management (IPv4), multicast route management (IPv6), IGMP snooping, MLD snooping, static multicast MAC address, multicast VLAN, multicast network management.
Rate and give feedback:
Huawei uses machine translation combined with human proofreading to translate this document to different languages in order to help you better understand the content of this document. Note: Even the most advanced machine translation cannot match the quality of professional translators. Huawei shall not bear any responsibility for translation accuracy and it is recommended that you refer to the English document (a link for which has been provided).
MSDP Packets

MSDP Packets

MSDP packets are encapsulated in TCP packets and are in the format of Type Length Value (TLV), as shown in Figure 6-2.

Figure 6-2 Format of MSDP packets

  • Type: indicates the packet type. Table 6-1 lists types of MSDP packets.
  • Length: indicates the packet length.
  • Value: indicates the packet content that depends on the packet type.
Table 6-1 Types of MSDP packets


MSDP Packet Type


Major Information Contained




Carries multiple groups of (S, G) entries and is transmitted among several RPs.

  • IP address of the source RP.
  • Number of (S, G) entries contained in an SA message.
  • List of active (S, G) entries in the domain.

Encapsulates PIM-SM multicast data.

  • IP address of the source RP.

  • PIM-SM multicast data.


Source-Active Request


Actively requests (S, G) list of a specified group G to reduce the delay for joining the group.

Address of the group G.


Source-Active Response


Responds to SA request messages.

  • IP address of the source RP.
  • Number of (S, G) entries contained in an SA-Resp message.
  • List of active (S, G) entries in the domain.



Maintains MSDP peer connections. The Keepalive packet is sent only when no other protocol packet is exchanged between MSDP peers.




This packet type is reserved and used as Notification messages at present.



Traceroute in Progress

Traces and detects the RPF path along which SA messages are transmitted.

  • IP address of the source RP.
  • List of active (S, G) entries in the domain.
  • Search ID
  • Returned search information
  • Number of hops


Traceroute Reply

As described in Table 6-1, SA messages carry (S, G) information and encapsulate multicast packets. MSDP peers share (S, G) information by exchanging SA messages. If an SA message contains only (S, G) information, remote users may not receive multicast data because the (S, G) entry has already timed out when reaching the remote domain. If multicast data packets are encapsulated in an SA message, remote users can still receive multicast data when the (S, G) entry times out.

When a new user joins the group, the user must wait for the SA message sent by the MSDP peer in the next period because SA messages are sent periodically. To reduce the delay for the new user to join the source SPT, MSDP supports SA request and response messages of Type 2 and Type 3 to improve the update efficiency of active source information.

Updated: 2019-04-20

Document ID: EDOC1100074724

Views: 38795

Downloads: 13

Average rating:
This Document Applies to these Products
Related Version
Related Documents
Previous Next