Dell PowerEdge FX2 Dell PowerEdge FN I/O Aggregator Configuration Guide 9.6(0 - Page 182

Fetching Dynamic MAC Entries using SNMP, MIB Object, Description

Page 182 highlights

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 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 18. 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 nondefault VLANs. dot3aCurAggFdb Table .1.3.6.1.4.1.6027.3.2. 1.1.5 F10-LINKAGGREGATION -MIB List the learned MAC addresses of aggregated links (LAG). In the following example, R1 has one dynamic MAC address, learned off 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 off 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 182 Simple Network Management Protocol (SNMP)

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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 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 18. 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 off 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 off 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----------------------
182
Simple Network Management Protocol (SNMP)