Dell S6000 FTOS 9.0(2.0) Configuration Guide for the System - Page 620

www.dell.com | support.dell.com By default, FTOS 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 FTOS 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: Figure 31-4. 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 Printed only for ACK packets 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:160.1N.o2c.h0anagdevi:n6u.p1d.a0te.p0acskeeqts: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 In FTOS Version, 7.5.1.0 use show ip ospf to confirm that RFC-2328 compliant OSPF flooding is enabled, as shown below. Figure 31-5. Enabling RFC-2328 Compliant OSPF Flooding FTOS#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. 598 | Open Shortest Path First (OSPFv2)