Cisco 15327 - Manual (Page 435)

26-3
Ethernet Card Software Feature and Configuration Guide, R7.2
Chapter 26 Configuring IEEE 802.17b Resilient Packet Ring
RPR-IEEE Framing Process
An RPR-IEEE is made up of dual counter-rotating rings (ringlets), one for clockwise or west data traffic
and one for counter-clockwise or east data traffic. The ringlets are identified as Ringlet 0 and Ringlet 1
in
Figure 26-1 . The west ringlet traffic is transmitted out the west interface and received by the east
interface. The east ringlet traffic is transmitted out the east interface and received by the west interface.
Only east-to-west or west-to-east transmission schemes are allowed.
Figure 26-1 Dual-Ring Structure
RPR-IEEE Framing Process
The ML-Series card transports data around the RPR-IEEE through packet-over-SONET/SDH (POS)
circuits. With POS, the RPR-IEEE frame is encapsulated into the SONET/SDH payload for transport
over the SONET/SDH topology. For more information about POS, see
Chapter 20, “POS on ONS
Ethernet Cards.”
Figure 26-2 illustrates the IEEE 802.17 basic data frame for IP only networks and the expected
IEEE 802.17b extended data frame used with bridging. The extended data frame adds an extended
destination address and extended source address to the basic data frame.
Ringlet 1 (east)
Ringlet 0 (west)
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