REVIEW DRAFT—CISCO CONFIDENTIAL
14-19
Cisco ONS 15454 SDH Reference Manual, R5.0
April 2008
Chapter14 Ethernet Operation
14.4 G-Series Circuit Configurations
14.4 G-Series Circuit Configurations
This section explains G-Series point-to-point circuits and ma nual cross-connects. Ethernet manual
cross-connects allow you to cross connect individual Ethernet circuits to an STM-N channel on the
ONS 15454 SDH optical interface and also to bridge non-ONS SDH network segments.

14.4.1 G-Series Point-to-Point Ethernet Circuits

G-Series cards support point-to-point circuit configurations (Figure 14-16) . Provisionable circuit sizes
are VC4, VC4-2c, VC4-3c, VC4-4c, VC4-8c, and VC4-16C. Each Ethernet port maps to a unique
STM-N circuit of the G-Series card.
Figure14-16 G-Series Point-to-Point Circuit
The G-Series supports any combination of up to four circuits from t he list of valid circuit sizes; however,
the circuit sizes can add up to no more than VC4-16.
Because of hardware constraints, the card imposes an additi onal restriction on the combinations of
circuits that can be dropped onto a G-Series card. These restrictions are transparently enforced by the
ONS 15454 SDH, and you do not need to keep track of restricted circuit combinations.
When a single VC4-8c terminates on a card, the remaining circuits on that card can be another single
VC4-8c or any combination of circuits of VC4-4c size or less that add up to no more than VC4-4 c (that
is, a total of 12 VC4s on the card).
If VC4-8c circuits are not being dropped on the card , the full VC4-16 bandwidth can be used with no
restrictions (for example, using either a single VC4-16C or 4 VC 4-4c circuits).
Note The VC4-8c restriction only applies when a single VC4- 8c circuit is dropped; therefore, you can easily
minimize the impact of this restriction. Group the VC4-8c circuits together on a card separate from
circuits of other sizes. The grouped circuits can be dropped on other G-Series cards on the
ONS 15454 SDH.
Caution G-Series cards do not connect with E-series cards.

14.4.2 G-Series Manual Cross-Connects

ONS 15454 SDHs require end-to-end CTC visibility between nodes for normal provisioning of Ethernet
circuits. When other vendors’ equipment sits between ONS 15454 SDHs, ope n system interconnection
(OSI)/Transient Addressing for Related Processes (TARP)-based equipment does not allow tunneling of
the ONS 15454 SDH TCP/IP-based DCC. To circumvent inconsistent DCCs, the Ethernet circuit must
be manually cross connected to an STM channel using the non-ONS network. Manual cross-connects
allows an Ethernet circuit to run from ONS node to ONS node while utilizing the non-ONS network
(Figure 14-17).
67830
Point-to-Point Circuit
ONS Node ONS Node
Gigabit Ethernet Gigabit Ethernet