Which S series switch will be selected to translate Type 7 LSAs into Type 5 LSAs if multiple ABRs are deployed in an NSSA

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Question: When multiple S series switches functioning as ABRs are deployed in an NSSA, which switch will be selected to translate Type 7 LSAs into Type 5 LSAs?
Answer: The system automatically selects the ABR with the largest router ID to translate LSAs.

Other related questions:
What is the purpose of a tag in an ASE-LSA and NSSA-LSA
In OSPF VPN multiple instances, a link-state advertisement (LSA) tag is used to prevent routing loops between PEs. In OSPF public network instances, the tag field does not prevent routing loops but is used to set the filtering conditions of routing policies. The rules of setting the tags of ASE-LSAs and NSSA-LSAs are as follows: In OSPF multiple instances, the route tag is set through the route-tag command. In OSPF public networks, the route tag is set through the default tag command. In either of the preceding two cases, you can run the import-route tag command to set the tag.

Common LSA types defined by OSPF of S series switches
Question: What are the common LSAs used in OSPF of S series switches? Why Type 6 LSAs do not exist? Answer: On S series switches supporting OSPF, OSPF uses the following types of LSAs: Type 1 LSA: router LSA Type 2 LSA: network LSA Type 3 LSA: summary LSA Type 4 LSA: ASBR-summary LSA Type 5 LSA: AS-external-LSA Type 7 LSA: NSSA AS-external-LSA OSPF packets were encoded based on Type-Length-Value (TLV). To enable other OSPF functions, you need to use LSAs of other types. Type 6 LSAs, indicating group-membership-LSAs, are used to identify multicast group members in Multicast Open Shortest Path First (MOSPF). Switches do not support Type 6 LSAs. Type 8 LSAs, indicating external-attributes-LSAs, are used to import BGP routes into OSPF processes for inter-operations and reserve information about BGP routes such as AS-Path. Switches do not support Type 8 LSAs. The Opaque LSA type is defined by RFC 2370 and can use the TLV structure. Applications such as OSPF Traffic Engineering (TE) are implemented by the Opaque LSA. The Type 9 LSA is the Opaque LSA flooding on a link. The Type 10 LSA is the Opaque LSA flooding within an area. The Type 11 LSA is the Opaque LSA flooding within an AS.

Common LSA types of OSPF
Common LSA types of OSPF are as follows: Type 1 LSA: router LSA. Generated by each router, describes the router's link status and cost, and advertised within the area to which it belongs. Type 2 LSA: network LSA. Describes the link status of all routers on the local network segment. Network-LSAs are generated by a designated router (DR) and advertised within the area to which the DR belongs. Type 3 LSA: summary LSA. Generated by ABR, describes all routes in the area, and advertised to other relevant areas. Type 4 LSA: ASBR-summary LSA. An ASBR-summary-LSA describes routes to the ASBR in an area. The routes are advertised to all areas except the area to which the ASBR belongs. Type 5 LSA: AS-external-LSA. Describes AS external routes, which are advertised to all areas except stub areas and NSSAs. AS-external-LSAs are generated by an ASBR. Type 7 LSA: NSSA AS-external-LSA. Describes AS external routes. NSSA-LSAs are generated by an ASBR and advertised only within NSSAs. The original OSPF packet coding is not Type Length Value (TLV)-based. For the extension of OSPF functions, only the LSA types of OSPF can be extended. Type 6 LSAs are Group-Membership-LSAs used to identify multicast group membership in the Multicast Open Shortest Path First (MOSPF) protocol. Type 6 LSAs are not supported on the firewall. Type 8 LSAs are External-Attributes-LSAs used to redistribute Border Gateway Protocol (BGP) routes into OSPF and reserve the BGP autonomous system (AS) path information. Type 8 LSAs are not supported on the firewall. RFC 2370 defines an important LSA type, namely, Opaque LSA, which allows for TLV-like structures. OSPF applications, such as OSPF traffic engineering, are based on the Opaque LSA extension abilities: Type 9 LSAs are Opaque LSAs that are advertised within the local link only; Type 10 LSAs are Opaque LSAs that are advertised within the local area only; Type 11 LSAs, similar to Type 5 LSAs, are Opaque LSAs that are advertised within the local AS.

Set the interval at which OSPF LSAs are retransmitted on S series switches
An OSPF-enabled S series switch sends an acknowledgement packet after receiving an LSA packet. If a device does not receive any acknowledgement packet, it retransmits the LSA to its peer device. The link-state retransmit interval parameter specifies the interval at which the LSA is retransmitted. The default value is 5, in seconds. You can run the ospf timer retransmit interval command in the interface view to reset a value.

License classification on S series switch
Licenses are classified as follows: Depending on purpose, licenses are classified into commercial (COMM) licenses and non-commercial (DEMO) licenses. Commercial license Generally, these licenses are purchased according to contracts, and are permanently valid. Non-commercial license These licenses are used for special purposes such as testing and trial, and are strictly controlled. Depending on authority, licenses are classified into feature licenses and capacity licenses. Feature license License-controlled features cannot be used without a license. An enhanced feature takes effect only after the value-added feature or another enhanced feature it depends on takes effect. Therefore, both the license for the enhanced function and the license for the dependent function must be installed. Capacity license These licenses are used to expand dynamic resources on the product. A capacity license takes effect only after the corresponding feature takes effect. If the feature is a license-controlled one, the license for the feature must be loaded before the capacity license. Customers can choose not to purchase a capacity license and use the default number of resources supported by the product, or purchase one or more licenses to obtain the total number of resources supported by the purchased licenses.

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