Fetch Dynamic Mac Entries Using Snmp - Dell C9000 Series Networking Configuration Manual

Fetch Dynamic MAC Entries using SNMP

Dell Networking supports the RFC 1493 dot1d table for the default VLAN and the dot1q table for all other
VLANs.
NOTE: The 802.1q Q-BRIDGE MIB defines VLANs regarding 802.1d, as 802.1d itself does not define them.
As a switchport must belong a VLAN (the default VLAN or a configured VLAN), all MAC address learned on
a switchport are associated with a VLAN. For this reason, the Q-Bridge MIB is used for MAC address query.
Moreover, specific to MAC address query, the MAC address indexes dot1dTpFdbTable only for a single
forwarding database, while dot1qTpFdbTable has two indices — VLAN ID and MAC address — to allow for
multiple forwarding databases and considering that the same MAC address is learned on multiple VLANs.
The VLAN ID is added as the first index so that MAC addresses are read by the VLAN, sorted
lexicographically. The MAC address is part of the OID instance, so in this case, lexicographic order is
according to the most significant octet.
Table 86. MIB Objects for Fetching Dynamic MAC Entries in the Forwarding Database
MIB Object
dot1dTpFdbTable
dot1qTpFdbTable
dot3aCurAggFdb Table
In the following example, R1 has one dynamic MAC address, learned off of port TenGigabitEthernet 1/21,
which a member of the default VLAN, VLAN 1. The SNMP walk returns the values for dot1dTpFdbAddress,
dot1dTpFdbPort, and dot1dTpFdbStatus.
Each object is comprised of an OID concatenated with an instance number. In the case of these objects, the
instance number is the decimal equivalent of the MAC address; derive the instance number by converting
each hex pair to its decimal equivalent. For example, the decimal equivalent of E8 is 232, and so the instance
number for MAC address 00:01:e8:06:95:ac is.0.1.232.6.149.172.
The value of dot1dTpFdbPort is the port number of the port off which the system learns the MAC address. In
this case, of TenGigabitEthernet 1/21, the manager returns the integer 118.
Example of Fetching MAC Addresses Learned on the Default VLAN Using SNMP
----------------MAC Addresses on Force10 System------------------
R1_E600#show mac-address-table
VlanId Mac Address
1 00:01:e8:06:95:ac Dynamic
----------------Query from Management Station----------------------
>snmpwalk -v 2c -c techpubs 10.11.131.162 .1.3.6.1.2.1.17.4.3.1
SNMPv2-SMI::mib-2.17.4.3.1.1.0.1.232.6.149.172 = Hex-STRING: 00 01 E8 06 95 AC
OID
.1.3.6.1.2.1.17.4.3
.1.3.6.1.2.1.17.7.1.2. 2
.1.3.6.1.4.1.6027.3.2. 1.1.5
Type Interface
Te 1/21
MIB
Q-BRIDGE MIB
Q-BRIDGE MIB
F10-LINK-
AGGREGATION -MIB
State
Active
Simple Network Management Protocol (SNMP)
Description
List the learned unicast
MAC addresses on the
default VLAN.
List the learned unicast
MAC addresses on non-
default VLANs.
List the learned MAC
addresses of aggregated
links (LAG).
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