Administrator Guide

Examples of OSPF 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
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
To conrm that you enabled RFC-2328–compliant OSPF ooding, 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, signicantly 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-congurable.
Setting 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.
The OSPF dead interval value is, by default, set to 40 secondsand is independent of the OSPF hello interval. Conguring a hello interval
does not change the dead interval in the system. In contrast, the OSPF dead interval on a Cisco router is, by default, four times as long as
the hello interval. Changing the hello interval on the Cisco router automatically changes the dead interval.
To ensure equal intervals between the routers, use the following command.
• Manually set the dead interval of the Dell Networking router to match the Cisco conguration.
INTERFACE mode
ip ospf dead-interval <x>
666
Open Shortest Path First (OSPFv2 and OSPFv3)