Ospf Nonstop Forwarding - Cisco Catalyst 3560-X Software Configuration Manual

Chapter 1 Configuring IP Unicast Routing
Table 1-5 Default OSPF Configuration (continued)
Feature
Timers shortest path first (spf)
Virtual link
1. NSF = Nonstop forwarding.
2. OSPF NSF awareness is enabled for IPv4 on Catalyst 3750-E and 3560-E switches running the IP services feature set.
OSPF for Routed Access
With Cisco IOS Release 12.2(55)SE, the IP Base image supports OSPF for routed access. The IP services
image is required if you need multiple OSPFv2 and OSPFv3 instances without route restrictions.
Additionally, the IP services image is required to enable the multi-VRF-CE feature.
OSPF for Routed Access is specifically designed so that you can extend Layer 3 routing capabilities to
the wiring closet.
OSPF for Routed Access supports only one OSPFv2 and one OSPFv3 instance with a combined total of
Note
200 dynamically learned routes. The IP Base image provides OSPF for routed access.
However, these restrictions are not enforced in this release.
With the typical topology (hub and spoke) in a campus environment, where the wiring closets (spokes)
are connected to the distribution switch (hub) that forwards all nonlocal traffic to the distribution layer,
the wiring closet switch need not hold a complete routing table. A best practice design, where the
distribution switch sends a default route to the wiring closet switch to reach interarea and external routes
(OSPF stub or totally stub area configuration) should be used when OSPF for Routed Access is used in
the wiring closet.
For more details, see the "High Availability Campus Network Design—Routed Access Layer using
EIGRP or OSPF" document.

OSPF Nonstop Forwarding

The switch or switch stack supports two levels of nonstop forwarding (NSF):
•
•
OL-25303-03
Default Setting
spf delay: 5 seconds.; spf-holdtime: 10 seconds.
No area ID or router ID defined.
Hello interval: 10 seconds.
Retransmit interval: 5 seconds.
Transmit delay: 1 second.
Dead interval: 40 seconds.
Authentication key: no key predefined.
Message-digest key (MD5): no key predefined.
OSPF NSF Awareness, page 1-30
OSPF NSF Capability, page 1-30
Catalyst 3750-X and 3560-X Switch Software Configuration Guide
Configuring OSPF
1-29