Reference Guide

Open Shortest Path First (OSPFv2) | 661
Fast Convergence (OSPFv2, IPv4 only)
Fast Convergence allows you to define the speeds at which LSAs are originated and accepted, and reduce
OSPFv2 end-to-end convergence time. Dell Networking OS enables you to accept and originate LSAa as
soon as they are available to speed up route information propagation.
Note that the faster the convergence, the more frequent the route calculations and updates. This will impact
CPU utilization and may impact adjacency stability in larger topologies.
Multi-Process OSPF (OSPFv2, IPv4 only)
Multi-Process OSPF is supported on the S5000 switch for 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 different domains,
and creating smaller domains for easier management. The S5000 support 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 must be in Layer-3 mode for the number of processes created. For example, if 5
OSPFv2 processes are created on a system, there must be at least 5 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 SNMP requests and
send SNMP traps. The
mib-binding command identifies one of the OSPVFv2 processes as the process
responsible for SNMP management. If the
mib-binding command is not specified, the first OSPFv2 process
created manages the SNMP processes and traps.
RFC-2328 Compliant OSPF Flooding
In OSPF, flooding is the most resource-consuming task. The flooding algorithm described in RFC 2328
requires that OSPF flood LSAs on all interfaces, as governed by LSA's flooding scope. (Refer to Section
13 of the RFC.) When multiple direct links connect two routers, the RFC 2328 flooding algorithm
generates significant redundant information across all links.
By default, Dell Networking OS implements an enhanced flooding procedure which dynamically and
intelligently detects when to optimize flooding. Wherever possible, the OSPF task attempts to reduce
flooding overhead by selectively flooding on a subset of the interfaces between two routers.
If RFC 2328 flooding behavior is required, enable it by using the command
flood-2328 in ROUTER OSPF
mode. When enabled, this command configures Dell Networking OS to flood LSAs on all interfaces.
Confirm RFC 2328 flooding behavior by using the command
debug ip ospf packet and look for output
similar to the following: