User guide

September 2009
Page 40 of 79 OmniSwitch 6400/6850/6855/9000/9000E—Release 6.4.2.R01
Port Mapping – Unknown Unicast Flooding
By default, unknown unicast traffic is flooded to the user ports of a port mapping session from all the
switch ports, not just the network ports for the session. There is now a port mapping option to enable or
disable unknown unicast flooding from network ports to user ports.
NTP Client
The 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
accuracies 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/OSPFv3
Open Shortest Path First version 3 (OSPFv3) is available. 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
considered 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. OSPF adjacencies over non-broadcast links are also supported.
In addition, OSPFv2 supports graceful (hitless) support during failover, which is the time period
between the restart and the reestablishment of adjacencies after a planned (e.g., the users performs the
takeover) or unplanned (e.g., the primary management module unexpectedly fails) failover. Note that
OSPFv3 does not support graceful restart.
Partitioned Switch Management
A user account includes a login name, password, and user privileges. The privileges determine whether
the user has read or write access to the switch, and which command domains and command families
the user is authorized to execute on the switch. The privileges are sometimes referred to as
authorization; the designation of particular command families or domains for user access is sometimes
referred to as partitioned management.
Per-VLAN DHCP Relay
It is possible to configure multiple DHCP relay (ip helper) addresses on a per-vlan basis. For the Per-
VLAN service, identify the number of the VLAN that makes the relay request. You may identify one
or more server IP addresses to which DHCP packets will be sent from the specified VLAN. Both
standard and per VLAN modes are supported.
PIM-SM/PIM-DM/PIM-SSM
Protocol-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 supported. PIM-DM packets are transmitted on the same socket as PIM-SM pack-
ets, as both use the same protocol and message format. Unlike PIM-SM, in PIM-DM there are no peri-
odic joins transmitted; only explicitly triggered prunes and grafts. In addition, there is no Rendezvous
Point (RP) in PIM-DM.