ASIC_DB Exploration

Use targeted queries (SCAN, never KEYS *) to locate route- and next-hop-related objects in ASIC_DB, follow their OID references, translate virtual OIDs to real ones, and articulate which parts are human-readable versus implementation-oriented — reinforcing that ASIC_DB is a sync-path representation, not the silicon.

Prerequisites: Lessons 3.3 and 3.4 complete. · At least one installed route with a resolved next hop.

Tasks

1. 1

   Enumerate object types present (bounded, safe)

   Get a feel for what object types exist without dumping the whole DB.

   SONiC DBlist distinct object-type prefixes; SCAN, not KEYS * Copy

   redis-cli -n 1 SCAN 0 MATCH 'ASIC_STATE:SAI_OBJECT_TYPE_*' COUNT 1000 | sed 's/:.*//' | sort -u

   Expected:

   • A list of SAI object types: ROUTE_ENTRY, NEXT_HOP, NEXT_HOP_GROUP, ROUTER_INTERFACE, NEIGHBOR_ENTRY, PORT, VLAN, FDB_ENTRY, etc.

   What happened internally: SCAN iterates in bounded chunks and does not block Redis the way KEYS * can. On a busy system this discipline matters.

2. 2

   Locate route-related objects

   SONiC DB Copy

   redis-cli -n 1 SCAN 0 MATCH 'ASIC_STATE:SAI_OBJECT_TYPE_ROUTE_ENTRY*' COUNT 500

   SONiC DBnote PACKET_ACTION and NEXT_HOP_ID Copy

   redis-cli -n 1 HGETALL 'ASIC_STATE:SAI_OBJECT_TYPE_ROUTE_ENTRY:{...}'

   Expected:

   • Route entries with a human-readable destination prefix inside the key and an opaque next-hop OID attribute.

   What happened internally: The prefix in the key is human-readable; the next-hop reference is an implementation-oriented VID. Both live in the same object.

3. 3

   Locate next-hop and next-hop-group objects

   SONiC DB Copy

   redis-cli -n 1 SCAN 0 MATCH 'ASIC_STATE:SAI_OBJECT_TYPE_NEXT_HOP:*' COUNT 500

   SONiC DBpresent when ECMP is in use Copy

   redis-cli -n 1 SCAN 0 MATCH 'ASIC_STATE:SAI_OBJECT_TYPE_NEXT_HOP_GROUP*' COUNT 500

   Expected:

   • Next-hop objects referencing a RIF and IP; next-hop-group objects (if ECMP) with members referencing next hops.

   What happened internally: Next-hop groups are the unit of ECMP. Their members reference individual next-hop objects — the fan-out point of the graph.

4. 4

   Identify references and translate VID→RID

   SONiC DBvirtual → real OID (maintained by syncd) Copy

   redis-cli -n 1 HGET VIDTORID oid:0x...

   SONiC DBhow many objects are mapped Copy

   redis-cli -n 1 HLEN VIDTORID

   Expected:

   • A real OID returned for a given virtual OID; a count of mapped objects.

   What happened internally: VIDTORID/RIDTOVID are the abstraction boundary: ASIC_DB speaks in virtual IDs; syncd maps them to the vendor SAI's real handles.

5. 5

   Classify human-readable vs implementation-oriented

   Write two short lists: (a) content a network engineer can read directly (prefixes, IPs, MACs, port names), and (b) content that is implementation-oriented (opaque OIDs, VID↔RID maps, internal attribute enums).

   Expected:

   • Two short lists that make the abstraction boundary explicit.

   What happened internally: This is the conceptual payoff: ASIC_DB is a faithful record of the SAI request/ack graph — part readable, part opaque — but still a database, not the transistors.