Cisco Cisco ONS 15454 SONET Multiservice Provisioning Platform (MSPP) Guía De Diseño

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paths.  Without GEC, STP only permits a single non-blocked path.  GEC can also provide G-
Series card-level protection or redundancy because it can support a group of ports on different 
cards (or different nodes) so that if one port or card has a failure, then traffic is re-routed over the 
other port or card. 
 

 
G-Series Ethernet cards support point-to-point circuits and Ethernet manual cross-connects. 
Ethernet manual cross-connects allow you to cross connect individual Ethernet circuits to an STS 
channel on the ONS 15454 optical interface and also to bridge non-ONS SONET network 
segments.  G-Series cards do not interoperate with the E-series cards.  Circuits created on a G-
Series card must terminate on another G-Series card. 
 
Point-to-Point Ethernet Circuits 
 
Figure 5-17 shows the G-Series Ethernet cards supporting a point-to-point circuit configuration.  
Provisionable circuit sizes are STS 1, STS 3c, STS 6c, STS 9c, STS 12c, STS 24c and STS 48c.  
Each Ethernet port maps to a unique STS circuit on the SONET side of the G-Series card. 
 

 

 

 
G-Series cards support any combination of up to four circuits from the list of valid circuit sizes, 
however the circuit sizes can add up to no more than 48 STSs.  Due to hardware constraints, the 
card imposes additional restrictions on the combinations of circuits that can be dropped onto a 
G1000-4 card.  These restrictions are transparently enforced by the ONS 15454, and you do not 
need to keep track of restricted circuit combinations. 
 
The restriction occurs when a single STS-24c is dropped on a card.  In this instance, the 
remaining circuits on that card can be another single STS-24c or any combination of circuits of 
STS-12c size or less that add up to no more than 12 STSs (i.e. a total of 36 STSs on the card). 
No circuit restrictions are present, if STS-24c circuits are not being dropped on the card.  The full 
48 STSs bandwidth can be used (for example using either a single STS-48c or 4 STS-12c 
circuits). 
 
Since the restrictions only apply when STS-24cs are involved but do not apply to two STS-24c 
circuits on a card, you can easily minimize the impact of these restrictions.  Group the STS-24c 
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. 
 

 G-Series cards use STS cross-connects only.  No VT level cross-connects are used. 

 

 All SONET side STS circuits must be contiguous.