Cisco 15327 - Manual (Page 334)

20-2
Ethernet Card Software Feature and Configuration Guide, R7.2
Chapter 20 POS on ONS Ethernet Cards
POS Interoperability
Figure 20-1 Ethernet to POS Process on ONS Node
ONS Ethernet cards all use POS. The Ethernet frame comes into the card on a standard Fast Ethernet or
Gigabit Ethernet port and is processed through the ONS Ethernet card’s framing mechanism and
encapsulated into a POS frame. When the POS frame exits, the ONS Ethernet card in a POS circuit, this
circuit is treated as any other SONET circuit (STS) or SDH circuit (VC) in the ONS node. It is
cross-connected and rides the SONET/SDH signal out the port of an optical card and across the
SONET/SDH network.
The destination of the POS circuit is an ONS Ethernet card or other device that supports a POS interface.
The POS frames received by the destination card have the data packets stripped out and processed into
Ethernet frames. The Ethernet frames are then sent to a standard Ethernet port of the ONS Ethernet card
and transmitted onto an Ethernet network.
The G-Series, CE-Series, and E-Series (configured in port-mapper mode) ONS Ethernet cards map this
SONET/SDH or POS circuit directly to one of the card’s Ethernet ports. The ML-Series and E-Series
(configured in EtherSwitch mode) cards include the POS port as a switchport in a switching fabric that
includes the standard Ethernet ports on the card.
POS Interoperability
In addition to POS circuits between Ethernet cards of the same family, POS circuits between some
Ethernet cards of different families are possible. The Cisco Transport Controller (CTC) circuit creation
wizard shows available interoperable Ethernet cards under the destination card options, when a specific
Ethernet card type is chosen as the circuit creation source card. You cannot mix circuits from an SDH
node with circuits from a SONET node. POS circuits can be created between the mapper-type cards and
the switch-type ONS Ethernet cards.
For Ethernet card POS interoperability, three main POS port characteristics must match:
• POS encapsulation
• CRC size
• Framing Mode
Ethernet Card
ONS Node
XC Card Optical Card
Ethernet
POS
virtual
ports
Ethernet
ports
Optical
ports
POS Framing
and Encapsulation
SONET/SDH
Ethernet riding in
STS (VC) circuit
SONET/SDH circuit
multiplexed
onto Optical Card
Optical card port transmits
SONET/SDH signal
containing data frame
across SONET/SDH network
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