Software Supported
OmniSwitch 6800/6850/9000—Release 6.1.3.R01 page 27
Multicast boundaries confine scoped multicast addresses to a particular domain. Confining scoped
addresses helps to ensure that multicast traffic passed within a multicast domain does not conflict with
multicast users outside the domain.
PIMPIM-SSMProtocol-Independent Multicast (PIM) is an IP multicast routing protocol that uses routing information
provided by unicast routing protocols, such as RIP and OSPF. PIM is “protocol-independent” because it
does not rely on any particular unicast routing protocol. Sparse mode PIM (PIM-SM) contrasts with
flood-and-prune dense mode multicast protocols, such as DVMRP and PIM Dense Mode (PIM-DM) in
that multicast forwarding in PIM-SM is initiated only via specific requests, referred to as Join messages.
PIM-DM for IPv4 is now supported with the 6.1.3.R01 release. PIM-DM packets are transmitted on the
same socket as PIM-SM packets, as both use the same protocol and message format. Unlike PIM-SM, in
PIM-DM there are no periodic joins transmitted; only explicitly triggered prunes and grafts. In addition,
there is no Rendezvous Point (RP) in PIM-DM.
Protocol Independent Multicast Source-Specific Multicast (PIM-SSM) is a highly-efficient extension of
PIM. SSM, using an explicit channel subscription model, allows receivers to receive multicast traffic
directly from the source; an RP tree model is not used. In other words, a Shortest Path Tree (SPT)
between the receiver and the source is created without the use of a Rendezvous Point (RP).
Multinetting
This feature allows IP traffic from multiple subnets to coexist on the same VLAN. A network is said to be
multinetted when multiple IP subnets are brought together within a single broadcast domain (VLAN). It is
possible to assign up to eight different IP interfaces per VLAN.
NTP ClientThe Network Time Protocol (NTP) is used to synchronize the time of a computer client or server to
another server or reference time source, such as a radio or satellite receiver. It provides client time accura-
cies within half a second on LANs and WANs relative to a primary server synchronized to Universal
Coordinated Time (UTC) (via a Global Positioning Service receiver, for example).
OSPFv2/OSPFv3Open Shortest Path First version 3 (OSPFv3) is now available with the 6.1.3.R01 release on the
OmniSwitch 6850 Series and OmniSwitch 9000 Series. OSPFv3 is an extension of OSPF version 2
(OSPFv2) that provides support for networks using the IPv6 protocol. OSPFv2 is for IPv4 networks.
Both versions of OSPF are shortest path first (SPF), or link-state, protocols for IP networks. Also consid-
ered interior gateway protocols (IGP), both versions distribute routing information between routers in a
single Autonomous System (AS). OSPF chooses the least-cost path as the best path. OSPF is suitable for
complex networks with a large number of routers by providing faster convergence, loop free routing, and
equal-cost multi-path routing where packets to a single destination can be sent to more than one interface
simultaneously.
The following features are also supported by both versions of OSPF:
•Graceful (Hitless) Support During Failover, which is the time period between the restart and the rees-
tablishment of adjacencies after a planned (e.g., the users performs the takeover) or unplanned (e.g., the
primary management module unexpectedly fails) failover.
•OSPF adjacencies over non broadcast links.