Deployment Guide

The value 40 is in the rst set of 7 hex pairs, indicating that these ports are in Stack Unit 0. The hex value 40 is 0100 0000 in binary. As
described, the left-most position in the string represents Port 1. The next position from the left represents Port 2 and has a value of 1,
indicating that Port 0/2 is in VLAN 10. The remaining positions are 0, so those ports are not in the VLAN.
Fetching Dynamic MAC Entries using SNMP
The Aggregator supports the RFC 1493 dot1d table for the default VLAN and the dot1q table for all other VLANs.
NOTE: The table contains none of the other information provided by the show vlan command, such as port speed or whether the
ports are tagged or untagged.
NOTE: The 802.1q Q-BRIDGE MIB denes VLANs regarding 802.1d, as 802.1d itself does not dene them. As a switchport must
belong a VLAN (the default VLAN or a congured 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, specic 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 rst 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 signicant octet.
Table 67. MIB Objects for Fetching Dynamic MAC Entries in the Forwarding Database
MIB Object OID MIB Description
dot1dTpFdbTable .1.3.6.1.2.1.17.4.3 Q-BRIDGE MIB List the learned unicast MAC
addresses on the default VLAN.
dot1qTpFdbTable .1.3.6.1.2.1.17.7.1.2. 2 Q-BRIDGE MIB List the learned unicast MAC
addresses on non-default
VLANs.
dot3aCurAggFdb Table .1.3.6.1.4.1.6027.3.2. 1.1.5 F10-LINK-AGGREGATION -MIB List the learned MAC addresses
of aggregated links (LAG).
In the following example, R1 has one dynamic MAC address, learned o of port TenGigabitEthernet 0/7, which is 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 o which the system learns the MAC address. In this case, of
TenGigabitEthernet 0/7, the manager returns the integer 118.
Example of Fetching Dynamic MAC Addresses on the Default VLAN
-----------------------------MAC Addresses on Dell Networking
System-------------------------------
Dell#show mac-address-table
VlanId Mac Address Type Interface State
1 00:01:e8:06:95:ac Dynamic Tengig 0/7 Active
----------------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
Example of Fetching Dynamic MAC Addresses on a Non-default VLANs
756
Simple Network Management Protocol (SNMP)