Chapter 3 Topology
Topology-Related Parameters
Cisco SCE 1000 2xGBE Installation and Configuration Guide
OL-7821-05
3-7
Maintaining the Network Links vs Maintaining SCE 1000 Platform Functionality
When a single
SCE 1000
is deployed, the user may decide that in case of a failure, maintaining
the network link is more important than providing the
SCE 1000
functionality. In this scenario,
when the
SCE 1000
detects a failure that requires a reboot process for recovering, it immediately
switches to Bypass mode, allowing all traffic to bypass the
SCE 1000
. The
SCE 1000
stays in
Bypass mode maintaining the network link, albeit without
SCE 1000
processing, until the
SCE
1000
fully recovers from the failure and is ready to resume normal functioning.
Alternatively, the user may decide that the
SCE 1000
functionality is sufficiently crucial to
require severing the link if the
SCE 1000
platform fails. In this case, when the
SCE 1000
detects a
failure that requires a reboot process for recovering, it immediately switches to Cutoff mode,
stopping all traffic flow. The
SCE 1000
stays in Cutoff mode, halting all traffic, until it fully
recovers from the failure and is ready to resume normal functioning. In Cutoff the physical
interface is blocked, enabling the network device connected to the
SCE 1000
to sense that the link
is down.
Topology-Related Parameters
Refer to the following sections to determine the correct values for all topology-related parameters
before beginning run the initial setup of the
SCE 1000
.
Connection Mode Parameter
The connection mode parameter refers directly to the physical topology in which the
SCE 1000
is
installed. Installation is possible in either of the two following modes:
•
Inline
— The
SCE 1000
resides on the data link between the subscriber side and the network
side, thus both receiving and transmitting packets.
•
Receive-only
— The
SCE 1000
does not reside physically on the data link. Data is forwarded
to the
SCE 1000
via an external optical splitter. The
SCE 1000
itself receives only and does
not transmit.
Note
Default value =
Inline
The connection mode parameter is determined by the physical deployment of the
SCE 1000
as
follows:
•
Bump-in-the-wire installation =
Inline
connection mode.
•
External optical splitter installation =
Receive-only
connection mode.