Cisco 15327 - Manual (Page 395)

23-15
Ethernet Card Software Feature and Configuration Guide, R7.2
Chapter 23 E-Series and G-Series Ethernet Operation
E-Series Modes
Figure 23-12 Single-Card EtherSwitch Configuration
Port-Mapped (Linear Mapper)
Port-mapped mode, also referred to as linear mapper, configures the E-Series card to map a specific
E-Series Ethernet port to one of the card’s specific STS/VC circuits (
Figure 23-13 ). Port-mapped mode
ensures that Layer 1 transport has low latency for unicast, multicast, and mixed traffic. Ethernet and Fast
Ethernet on the E100T-G or E10/100-4 card operate at line-rate speed. Gigabit Ethernet transport is
limited to a maximum of 600 Mbps because the E1000-2-G card has a maximum bandwidth of
STS-12c/VC4-4c. Ethernet frame sizes up to 1522 bytes are also supported, which allow transport of
IEEE 802.1Q tagged frames. The larger maximum frame size of Q-in-Q frames (IEEE 802.1Q in IEEE
802.1Q wrapped frames) is not supported.
Figure 23-13 E-Series Mapping Ethernet Ports to STS/VC Circuits
Port-mapped mode disables Layer 2 functions supported by the E-Series in single-card and multicard
mode, including STP, VLANs, and MAC address learning. It significantly reduces the service-affecting
time for cross-connect and TCC2/TCC2P card switches.
Port-mapped mode does not support VLANs in the same manner as multicard and single-card mode. The
ports of E-Series cards in multicard and single-card mode can join specific VLANs. E-Series cards in
port-mapped mode do not have this Layer 2 capability and only transparently transport external VLANs
over the mapped connection between ports. An E-Series card in port-mapped mode does not inspect the
tag of the transported VLAN, so a VLAN range of 1 through 4096 can be transported in port-mapped
mode.
Port-mapped mode does not perform any inspection or validation of the Ethernet frame header. The
Ethernet CRC is validated, and any frame with an invalid Ethernet CRC is discarded.
ONS Node ONS Node
Router
Ethernet card 3
Router
Router
Router
Ethernet card 1
Ethernet card 4
Ethernet card 2
VLAN B
VLAN A
45132
SONET/SDH
ONS Node ONS Node
1:1 Ethernet port to STS/VC circuit mapping
83497