What is the default priority value used for electing the DR on an Nokia 7750 SR running OSPF on an Ethernet?

On a Nokia 7750 SR router, the default priority value for an OSPF interface on a broadcast network, such as Ethernet, is 1. This value is used in the Designated Router (DR) and Backup Designated Router (BDR) election process. A higher priority value increases the likelihood of a router being elected as the DR. The default value of 1 ensures that the router participates in the election process without any specific preference, adhering to the standard defined in RFC 2328.

A. Priority of 0: A priority of 0 explicitly prevents the router from participating in the DR/BDR election, making it ineligible to become a DR or BDR.
C. Priority of 64: This is not the default OSPF priority value on Nokia SR OS. While other protocols or vendors might use this value, it is incorrect for OSPF on a 7750 SR.
D. Priority of 255: This is the highest possible priority value. It is not a default and would be manually configured to give a router the highest preference in a DR/BDR election.

1. Nokia 7750 SR OS Router Configuration Guide, Release 22.10.R1: In the "OSPF Command Reference" section, under the config>router>ospf>area>interface context, the priority command is described. The documentation states: "This command configures the priority of the router for becoming the designated router. ... Default: 1". (Document ID: 3HE 18138 AAAC TQZZA, Section: OSPF Interface Commands)

2. RFC 2328 - OSPF Version 2: This foundational document for OSPF specifies the default behavior. In Appendix A.3.3, "Interface parameters," it defines RouterPriority as an 8-bit unsigned integer and states, "The default value for this parameter is 1."