Cisco 15327 - Manual (Page 258)

17-6
Ethernet Card Software Feature and Configuration Guide, R7.2
Chapter 17 Configuring Cisco Proprietary Resilient Packet Ring
MAC Address and VLAN Support
Figure 17-4 Cisco Proprietary RPR Frame Fields
MAC Address and VLAN Support
Cisco proprietary RPR increases the total number of MAC addresses supported because the MAC IDs of
packets that pass through an ML-Series card are not recorded by that ML-Series card. The ML-Series
card only records the MAC IDs of the packets that are bridged or stripped by that ML-Series card. This
allows a greater number of MAC addresses in the collective address tables of the Cisco proprietary RPR.
VLANs on Cisco proprietary RPR require less interface configuration than VLANs on STP and RSTP,
which require configuration on all the POS interfaces in the ring. Cisco proprietary RPR VLANs only
require configuration on SPR interfaces that bridge or strip packets for that VLAN.
Table 17-1 Definitions of RPR Frame Fields
Field Definition
Destination Station An eight-bit field specifying the MAC address of a specific ML-Series card in
the Cisco proprietary RPR as the destination. It has two well-known addresses:
0xff for Multicast DA-MAC and 0x00 for Unknown DA-MAC.
Source Station An eight-bit field specifying the MAC address of a specific ML-Series card in
the Cisco proprietary RPR as the source.
PRI A three-bit QoS class of service (CoS) field that establishes Cisco proprietary
RPR priority.
DE A one-bit field that specifies the discard eligible flag.
TTL A nine-bit field that specifies the frame’s time to live.
Type A field indicating whether the packet is data or control.
Destination ID Destination Station
Protocol (RPR V1)
Payload (Ethernet Frame)
134982
Source ID Source Station
PRI W TTL
Wrap Station RSVD Type
B
D
E
D
V
D
W
D
S
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0