Reference Guide

Table Of Contents
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 debug ip ospf packet command and look for
output similar to the following:
Enabling RFC-2328–Compliant OSPF Flooding
00:10:41 : OSPF(1000:00):
Rcv. v:2 t:5(LSAck) l:64 Acks 2 rid:2.2.2.2
aid:1500 chk:0xdbee aut:0 auk: keyid:0 from:Vl 1000
LSType:Type-5 AS External id:160.1.1.0 adv:6.1.0.0 seq:0x8000000c
LSType:Type-5 AS External id:160.1.2.0 adv:6.1.0.0 seq:0x8000000c
00:10:41 : OSPF(1000:00):
Rcv. v:2 t:5(LSAck) l:64 Acks 2 rid:2.2.2.2
aid:1500 chk:0xdbee aut:0 auk: keyid:0 from:Vl 100
LSType:Type-5 AS External id:160.1.1.0 adv:6.1.0.0 seq:0x8000000c
LSType:Type-5 AS External id:160.1.2.0 adv:6.1.0.0 seq:0x8000000c
00:10:41 : OSPF(1000:00):
Rcv. v:2 t:4(LSUpd) l:100 rid:6.1.0.0
aid:0 chk:0xccbd aut:0 auk: keyid:0 from:Te 10/21
Number of LSA:2
LSType:Type-5 AS External(5) Age:1 Seq:0x8000000c id:170.1.1.0 Adv:6.1.0.0
Netmask:255.255.255.0 fwd:0.0.0.0 E2, tos:0 metric:0
LSType:Type-5 AS External(5) Age:1 Seq:0x8000000c id:170.1.2.0 Adv:6.1.0.0
Netmask:255.255.255.0 fwd:0.0.0.0 E2, tos:0 metric:0
Example of the show ip ospf Command
To confirm that RFC-2328 compliant OSPF flooding is enabled, use the show ip ospf command.
Dell#show ip ospf
Routing Process ospf 1 with ID 2.2.2.2
Supports only single TOS (TOS0) routes
It is an Autonomous System Boundary Router
It is Flooding according to RFC 2328
SPF schedule delay 5 secs, Hold time between two SPFs 10 secs
Number of area in this router is 1, normal 0 stub 0 nssa 1
--More--
OSPF ACK Packing
The OSPF ACK packing feature bundles multiple LS acknowledgements in a single packet, significantly
reducing the number of ACK packets transmitted when the number of LSAs increases.
This feature also enhances network utilization and reduces the number of small ACK packets sent to a
neighboring router. OSPF ACK packing is enabled by default and non-configurable.
OSPF Adjacency with Cisco Routers
To establish an OSPF adjacency between Dell Networking and Cisco routers, the hello interval and dead
interval must be the same on both routers.
In the Dell Networking OS, the OSPF dead interval value is, by default, set to 40 seconds, and is
independent of the OSPF hello interval. Configuring a hello interval does not change the dead interval in
Dell Networking OS. In contrast, the OSPF dead interval on a Cisco router is, by default, four times as long
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Open Shortest Path First (OSPFv2)