Deprecate BlobSidecarsByRange/Root in Fulu (#4286)

Author: SunnysidedJ

specs/fulu/p2p-interface.md

@@ -26,6 +26,8 @@
         - [Distributed Blob Publishing using blobs retrieved from local execution layer client](#distributed-blob-publishing-using-blobs-retrieved-from-local-execution-layer-client)
   - [The Req/Resp domain](#the-reqresp-domain)
     - [Messages](#messages)
+      - [BlobSidecarsByRange v1](#blobsidecarsbyrange-v1)
+      - [BlobSidecarsByRoot v1](#blobsidecarsbyroot-v1)
       - [DataColumnSidecarsByRange v1](#datacolumnsidecarsbyrange-v1)
       - [DataColumnSidecarsByRoot v1](#datacolumnsidecarsbyroot-v1)
       - [GetMetaData v3](#getmetadata-v3)
@@ -215,6 +217,30 @@ When clients use the local execution layer to retrieve blobs, they SHOULD skip v
 
 #### Messages
 
+##### BlobSidecarsByRange v1
+
+**Protocol ID:** `/eth2/beacon_chain/req/blob_sidecars_by_range/1/`
+
+Deprecated as of `FULU_FORK_EPOCH + MIN_EPOCHS_FOR_BLOB_SIDECARS_REQUESTS`.
+
+During the deprecation transition period:
+
+- Clients MUST respond with a list of blob sidecars from the range `[min(current_epoch - MIN_EPOCHS_FOR_BLOB_SIDECARS_REQUESTS, FULU_FORK_EPOCH), FULU_FORK_EPOCH)` if the requested range includes any epochs in this interval.
+- Clients MAY respond with an empty list if the requested range lies entirely at or after `FULU_FORK_EPOCH`.
+- Clients SHOULD NOT penalize peers for requesting blob sidecars from `FULU_FORK_EPOCH`.
+
+##### BlobSidecarsByRoot v1
+
+**Protocol ID:** `/eth2/beacon_chain/req/blob_sidecars_by_root/1/`
+
+Deprecated as of `FULU_FORK_EPOCH + MIN_EPOCHS_FOR_BLOB_SIDECARS_REQUESTS`.
+
+During the deprecation transition period:
+
+- Clients MUST respond with blob sidecars corresponding to block roots from the range `[min(current_epoch - MIN_EPOCHS_FOR_BLOB_SIDECARS_REQUESTS, FULU_FORK_EPOCH), FULU_FORK_EPOCH)` if any of the requested roots correspond to blocks in this interval.
+- Clients MAY respond with an empty list if all requested roots correspond to blocks at or after `FULU_FORK_EPOCH`.
+- Clients SHOULD NOT penalize peers for requesting blob sidecars from `FULU_FORK_EPOCH`.
+
 ##### DataColumnSidecarsByRange v1
 
 **Protocol ID:** `/eth2/beacon_chain/req/data_column_sidecars_by_range/1/`