Service Manual

Fast Convergence (OSPFv2, IPv4 Only)
Fast convergence allows you to dene the speeds at which LSAs are originated and accepted, and reduce OSPFv2 end-to-end
convergence time.
Dell Networking OS allows you to accept and originate LSAa as soon as they are available to speed up route information propagation.
NOTE: The faster the convergence, the more frequent the route calculations and updates. This impacts CPU utilization
and may impact adjacency stability in larger topologies.
Multi-Process OSPFv2 (IPv4 only)
Multi-process OSPF is supported on the platform with Dell Networking OS version 7.8.1.0 and later, and is supported on OSPFv2
with IPv4 only. Multi-process OSPF is supported on the S6000–ON platform with Dell Networking OS version 9.7(0.0) and later, and
is supported on OSPFv2 with IPv4 only.
Multi-process OSPF allows multiple OSPFv2 processes on a single router. Multiple OSPFv2 processes allow for isolating routing
domains, supporting multiple route policies and priorities in dierent domains, and creating smaller domains for easier management.
The device supports up to 16 OSPFv2 processes.
Each OSPFv2 process has a unique process ID and must have an associated router ID. There must be an equal number of interfaces
and must be in Layer-3 mode for the number of processes created. For example, if you create ve OSPFv2 processes on a system,
there must be at least ve interfaces assigned in Layer 3 mode.
Each OSPFv2 process is independent. If one process loses adjacency, the other processes continue to function.
Processing SNMP and Sending SNMP Traps
Though there are may be several OSPFv2 processes, only one process can process simple network management protocol (SNMP)
requests and send SNMP traps.
NOTE: SNMP get request corresponding to the OspfNbrOption feild in the OspfNbrTable returns a value of 66.
RFC-2328 Compliant OSPF Flooding
In OSPF, ooding is the most resource-consuming task. The ooding algorithm described in RFC 2328 requires that OSPF ood
LSAs on all interfaces, as governed by LSA’s ooding scope (refer to Section 13 of the RFC.)
When multiple direct links connect two routers, the RFC 2328 ooding algorithm generates signicant redundant information across
all links.
By default, Dell Networking OS implements an enhanced ooding procedure which dynamically and intelligently detects when to
optimize ooding. Wherever possible, the OSPF task attempts to reduce ooding overhead by selectively ooding on a subset of the
interfaces between two routers.
Enabling RFC-2328 Compliant OSPF Flooding
To enable OSPF ooding, use the following command.
When you enable this command, it congures Dell Networking OS to ood LSAs on all interfaces.
• Enable RFC 2328 ooding.
ROUTER OSPF mode
flood-2328
Example of Viewing the Debug Log for Flooding Behavior
To conrm RFC 2328 ooding behavior, use the debug ip ospf packet command. The following example shows no change in
the updated packets (shown in bold).
ACKs 2 (shown in bold) is printed only for ACK packets.
00:10:41 : OSPF(1000:00):
Rcv. v:2 t:5(LSAck) l:64 Acks 2 rid:2.2.2.2
542
Open Shortest Path First (OSPFv2 and OSPFv3)