RFC 2149 (rfc2149) - Page 3 of 18
Multicast Server Architectures for MARS-based ATM multicasting
Alternative Format: Original Text Document
RFC 2149 Multicast Server Architectures May 1997
3 MCS Architecture
The MCS acts as a proxy server which multicasts data received from a
source to the group members in the cluster. All multicast sources
transmitting to an MCS-based group send the data to the specified
MCS. The MCS then forwards the data over a point to multipoint VC
that it maintains to group members in the cluster. Each multicast
source thus maintains a single point-to-multipoint VC to the
designated MCS for the group. The designated MCS terminates one
point-to-multipoint VC from each cluster member that is multicasting
to the layer 3 group. Each group member is the leaf of the point-
to-multipoint VC originating from the MCS.
A brief introduction to possible MCS architectures has been presented
in [GA96]. The main contribution of that document concerning the MCS
approach is the specification of the MARS interaction with the MCS.
The next section lists control messages exchanged by the MARS and
MCS.
3.1 Control Messages exchanged by the MCS and the MARS
The following control messages are exchanged by the MARS and the MCS.
operation code Control Message
1 MARS_REQUEST
2 MARS_MULTI
3 MARS_MSERV
6 MARS_NAK
7 MARS_UNSERV
8 MARS_SJOIN
9 MARS_SLEAVE
12 MARS_REDIRECT_MAP
MARSMSERV and MARS-UNSERV are identical in format to the MARSJOIN
message. MARSSJOIN and MARS-SLEAVE are also identical in format to
MARSJOIN. As such, their formats and those of MARSREQUEST, MARS-
MULTI, MARSNAK and MARSREDIRECT-MAP are described in [GA96]. Their
usage is described in section 4. All control messages are LLC/SNAP
encapsulated as described in section 4.2 of [GA96]. (The "mar$"
notation used in this document is borrowed from [GA96], and indicates
a specific field in the control message.) Data messages are
reflected without any modification by the MCS.
Talpade & Ammar Informational