Cisco ONS 15454 SDH - Available Total Bandwidth for E-Series Modes; E-Series IEEE 802.3 Z Flow Control

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Cisco ONS 15454 and Cisco ONS 15454 SDH Ethernet Card Software Feature and Configuration Guide, R8.0
Chapter 23 E-Series and G-Series Ethernet Operation
E-Series IEEE 802.3z Flow Control
Available Total Bandwidth For E-Series Modes
Table 23-1 shows the total bandwidth available for E-Series modes on the ONS 15454 and ONS 15454
SDH.
E-Series IEEE 802.3z Flow Control
The E100T-G or E10/100-4 (operating in any mode) and the E1000-2-G (operating port-mapped mode)
support IEEE 802.3z symmetrical flow control and propose symmetric flow control when
autonegotiating with attached Ethernet devices. For flow control to operate, both the E-Series port and
the attached Ethernet device must be set to autonegotiation (AUTO) mode. The attached Ethernet device
might also need to have flow control enabled. The flow-control mechanism allows the E-Series to
respond to pause frames sent from external devices and send pause frames to external devices.
For the E100T-G or E10/100-4 (operating in any mode) and the E1000-2-G (operating port-mapped
mode), flow control matches the sending and receiving device throughput to that of the bandwidth of the
STS circuit. For example, a router might transmit to the Gigabit Ethernet port on the E-Series in
port-mapped mode. The data rate transmitted by the router might occasionally exceed 622 Mbps, but the
ONS 15454 circuit assigned to the E-Series port in port-mapped mode is a maximum of STS-12c (622.08
Mbps). In this scenario, the ONS 15454 sends out a pause frame and requests that the router delay its
transmission for a certain period of time.
Table 23-1 ONS 15454 E-Series Ethernet Circuit Sizes
ONS 15454
E-Series
Port-Mapped and
Single-Card
EtherSwitch
ONS 15454
E-Series
Multicard
EtherSwitch
ONS 15454 SDH
E-Series
Port-Mapped and
Single-Card
EtherSwitch
ONS 15454 SDH
E-Series
Multicard
EtherSwitch
STS-1 STS-1 VC4 VC4
STS-3c STS-3c VC4-2c VC4-2c
STS-6c STS-6c VC4-4c —
STS-12c — — —
Table 23-2 ONS 15454 E-Series Total Bandwidth Available
ONS 15454
E-Series
Port-Mapped
and Single-Card
EtherSwitch
ONS 15454
E-Series
Multicard
EtherSwitch
ONS 15454 SDH
E-Series
Port-Mapped
and Single-Card
EtherSwitch
ONS 15454 SDH
E-Series
Multicard
EtherSwitch
Combined total
of STS-12c
Combined
total of
STS-6c
Combined total
of VC4-4c
Combined total
of VC4-2c