Cisco NM-8B-U User Guide - Page 18

Feature Overview 16- and 36-Port Ethernet Switch Module for Cisco 2600 Series, Cisco 3600 Series, and Cisco 3700 Series Learning State A Layer 2 interface in the learning state prepares to participate in frame forwarding. The Layer 2 interface enters the learning state from the listening state. Figure 7 shows a Layer 2 interface in the learning state. Figure 7 Interface 2 in Learning State All segment frames Forwarding Station addresses Port 1 BPDUs Network management and data frames Filtering database System module Frame forwarding Station addresses Data frames BPDUs Port 2 Network management frames S5694 Learning All segment frames BPDU and network management frames A Layer 2 interface in the learning state performs as follows: • Discards frames received from the attached segment. • Discards frames switched from another interface for forwarding. • Incorporates end station location into its address database. • Receives BPDUs and directs them to the system module. • Receives, processes, and transmits BPDUs received from the system module. • Receives and responds to network management messages. Cisco IOS Release 12.2(2)XT, 12.2(8)T, and 12.2(15)ZJ 18