•
Type 7: External LSA
— Routers in an NSSA do not receive external LSAs from ABRs, but are allowed to send external routing
information for redistribution. They use Type 7 LSAs to tell the ABRs about these external routes, which the ABR then translates to
Type 5 external LSAs and floods as normal to the rest of the OSPF network.
•
Type 8: Link LSA (OSPFv3)
— This LSA carries the IPv6 address information of the local links.
•
Type 9: Link Local LSA (OSPFv2), Intra-Area-Prefix LSA (OSPFv3)
— For OSPFv2, this is a link-local "opaque" LSA as defined by
RFC2370. For OSPFv3, this LSA carries the IPv6 prefixes of the router and network links.
•
Type 11 - Grace LSA (OSPFv3)
— For OSPFv3 only, this LSA is a link-local “opaque” LSA sent by a restarting OSPFv3 router during a
graceful restart.
For all LSA types, there are 20-byte LSA headers. One of the fields of the LSA header is the link-state ID.
Each router link is defined as one of four types: type 1, 2, 3, or 4. The LSA includes a link ID field that identifies, by the network number and
mask, the object this link connects to.
Depending on the type, the link ID has different meanings.
•
1: point-to-point connection to another router/neighboring router.
•
2: connection to a transit network IP address of the DR.
•
3: connection to a stub network IP network/subnet number.
LSA Throttling
LSA throttling provides configurable interval timers to improve OSPF convergence times.
The default OSPF static timers (5 seconds for transmission, 1 second for acceptance) ensures sufficient time for sending and resending
LSAs and for system acceptance of arriving LSAs. However, some networks may require reduced intervals for LSA transmission and
acceptance. Throttling timers allow for this improved convergence times.
The LSA throttling timers are configured in milliseconds, with the interval time increasing exponentially until a maximum time has been
reached. If the maximum time is reached, the system, the system continues to transmit at the max-interval until twice the max-interval time
has passed. At that point, the system reverts to the start-interval timer and the cycle begins again.
When you configure the LSA throttle timers, syslog messages appear, indicating the interval times, as shown below for the transmit timer
(45000ms) and arrival timer (1000ms).
Mar 15 09:46:00: %STKUNIT0-M:CP %OSPF-4-LSA_BACKOFF: OSPF Process 10,Router lsa id
2.2.2.2 router-id 2.2.2.2 is backed off to transmit after 45000ms
Mar 15 09:46:06: %STKUNIT0-M:CP %OSPF-4-LSA_BACKOFF: OSPF Process 10,Router lsa id
3.3.3.3 rtrid 3.3.3.3 received before 1000ms time
NOTE:
The sequence numbers are reset when previously cleared routes that are waiting for the LSA throttle timer to expire are
re-enabled.
Router Priority and Cost
Router priority and cost is the method the system uses to “rate” the routers.
For example, if not assigned, the system selects the router with the highest priority as the DR. The second highest priority is the BDR.
•
Priority is a numbered rating 0 to 255. The higher the number, the higher the priority.
•
Cost is a numbered rating 1 to 65535. The higher the number, the greater the cost. The cost assigned reflects the cost should the
router fail. When a router fails and the cost is assessed, a new priority number results.
Open Shortest Path First (OSPFv2 and OSPFv3)
625
Содержание S4048T-ON
Страница 1: ...Dell Configuration Guide for the S4048 ON System 9 11 2 1 ...
Страница 148: ...Figure 10 BFD Three Way Handshake State Changes 148 Bidirectional Forwarding Detection BFD ...
Страница 251: ...Dell Control Plane Policing CoPP 251 ...
Страница 363: ... RPM Synchronization GARP VLAN Registration Protocol GVRP 363 ...
Страница 511: ...Figure 64 Inspecting the LAG Configuration Link Aggregation Control Protocol LACP 511 ...
Страница 512: ...Figure 65 Inspecting Configuration of LAG 10 on ALPHA 512 Link Aggregation Control Protocol LACP ...
Страница 515: ...Figure 67 Inspecting a LAG Port on BRAVO Using the show interface Command Link Aggregation Control Protocol LACP 515 ...
Страница 516: ...Figure 68 Inspecting LAG 10 Using the show interfaces port channel Command 516 Link Aggregation Control Protocol LACP ...
Страница 558: ...Figure 84 Configuring Interfaces for MSDP 558 Multicast Source Discovery Protocol MSDP ...
Страница 559: ...Figure 85 Configuring OSPF and BGP for MSDP Multicast Source Discovery Protocol MSDP 559 ...
Страница 560: ...Figure 86 Configuring PIM in Multiple Routing Domains 560 Multicast Source Discovery Protocol MSDP ...
Страница 564: ...Figure 88 MSDP Default Peer Scenario 2 564 Multicast Source Discovery Protocol MSDP ...
Страница 565: ...Figure 89 MSDP Default Peer Scenario 3 Multicast Source Discovery Protocol MSDP 565 ...
Страница 729: ...protocol spanning tree pvst no disable vlan 300 bridge priority 4096 Per VLAN Spanning Tree Plus PVST 729 ...
Страница 841: ...Figure 115 Single and Double Tag TPID Match Service Provider Bridging 841 ...
Страница 842: ...Figure 116 Single and Double Tag First byte TPID Match 842 Service Provider Bridging ...