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Cisco ONS 15454 SDH Reference Manual, R5.0
April 2008
Chapter10 Circuits and Tunnels
10.4.2 IP-Encapsulated Tunnels
Note A DCC does not function on a mixed network of ONS 15454 SDH nodes and ONS 15454 nodes. DCC
tunneling is required for ONS 15454 SDH nodes transporting data through ONS 15454 nodes.
Figure10-3 Traditional DCC Tunnel
When you create DCC tunnels, keep the following guidelines in mind:
•Each ONS 15454 SDH can have up to 84 DCC tunnel connections.
•Each ONS 15454 SDH can have up to 84 regenerator SDCC terminations.
•A regenerator SDCC that is terminated cannot be used as a DCC tunnel endpoint.
•A regenerator SDCC that is used as a DCC tunnel endpoint cannot be terminated.
•All DCC tunnel connections are bidirectional.
Note A multiplex SDCC cannot be used for tunneling if a data DCC is assigned.
10.4.2 IP-Encapsulated Tunnels
An IP-encapsulated tunnel puts an SDCC in an IP packet at a source node and dynamically routes the
packet to a destination node. A traditional DCC tunnel is configured as one dedicated path across a
network and does not provide a failure recovery mechanism if the p ath is down. An IP-encapsulated
tunnel is a virtual path, which adds protection when traffic travels between different networks.
IP-encapsulated tunneling has the potential of flooding the DCC network with traffic resulting in a
degradation of performance for CTC. The data originating from an IP tunnel can be throttled to a
user-specified rate, which is a percentage of the total SDCC bandwidth.
Each ONS 15454 SDH supports up to ten IP-encapsulated tunnels. You can convert a traditional DCC
tunnel to an IP-encapsulated tunnel or an IP-encapsulated tunnel to a traditional DCC tunnel. Only
tunnels in the DISCOVERED status can be converted.
Caution Converting from one tunnel type to the other is service-affecting.
Third party
equipment
Link 1
From (A)
Slot 3 (STM-1)
Port 1, RSDCC
To (B)
Slot 13 (STM-16)
Port 1, Tunnel 1
Node 1
71676
Third party
equipment
Link 2
From (A)
Slot 12 (STM-16)
Port 1, Tunnel 1
To (B)
Slot 13 (STM-16)
Port 1, Tunnel 1
Node 2
Link 3
From (A)
Slot 12 (STM-16)
Port 1, Tunnel 1
To (B)
Slot 3 (STM-1)
Port 1, RSDCC
Node 3