To set up Y-cable protection,
create a Y-cable protection group for two TXP, MXP, or Xponder cards using
Cisco Transport Controller (CTC). Next, connect the client ports of the two
cards physically with a Y-cable. The single client signal is sent into the RX
Y-cable and is split between the two TXP, MXP, or Xponder cards. The two TX
signals from the client side of the TXP, MXP, or Xponder cards are combined in
the TX Y-cable into a single client signal. Only the active card signal passes
through as the single TX client signal. CTC automatically turns off the laser
on the protect card to avoid signal interference where the Y-cable joins.
On the GE_XP, 10GE_XP,
GE_XPE, 10GE_XPE, and OTU2_XP cards, the Y-cable protection mechanism is
provisionable and can be set ON or OFF (OFF is the default mode).
When a signal fault is
detected, the protection mechanism software automatically switches between
paths. Y-cable protection also supports revertive and nonrevertive mode.
When an MXP_MR_2.5G,
MXP_MR_10DME_C, MXP_MR_10DME_L, AR_MXP, AR_XP, or AR_XPE card that is
provisioned with Y-cable protection is used on a storage ISL link (ESCON, FC1G,
FC2G, FC4G, FICON1G, FICON2G, FICON4G, or ISC-3 1/2G), a protection switchover
resets the standby port to active. This reset reinitialises the end-to-end link
to avoid any link degradation caused due to loss of buffer credits during
switchover and results in an end-to-end traffic hit of 15 to 20 seconds.
When using the MXP_MR_10DME_C
or MXP_MR_10DME_L card, enable the fast switch feature and use it with a Cisco
MDS storage switch to avoid this 15 to 20 second traffic hit. When enabling
fast switch on the MXP_MR_10DME_C or MXP_MR_10DME_L card, ensure that the
attached MDS switches have the buffer-to-buffer credit recovery feature
You can also use the
TXP_MR_2.5G card to avoid this 15 to 20 second traffic hit. When a Y-cable
protection switchover occurs, the storage ISL link does not reinitialize and
results in an end-to-end traffic hit of less than 50 ms.
AR_MXP, AR_XP, and AR_XPE
cards support Y-cable protection on the client ports, which are part of an
unprotected card mode. The Y-cable protection is not supported for video and
When using the AR_MXP, AR_XP,
or AR_XPE card on storage ISL link, use it with a Cisco MDS storage switch to
avoid this 15 to 20 second traffic hit.
When the active AR_MXP,
AR_XP, AR_XPE card is removed from the shelf, there is a traffic hit of 60 to
Y-cable connectors will not
work with electrical SFPs because Y-cables are made up of optical connectors
and it is not possible to physically connect them to an electrical SFP. Y-cable
protection is not supported on IB_5G.
There is a traffic hit of up
to a of couple hundred milliseconds on the MXP_MR_2.5G and MXP_MR_10DME cards
in Y-cable configuration when a fiber cut or SFP failure occurs on one of the
If you create a GCC on either
card of the protect group, the trunk port stays permanently active, regardless
of the switch state. When you provision a GCC, you are provisioning unprotected
overhead bytes. The GCC is not protected by the protect group.
Loss of Signal–Payload
(LOS-P) alarms, also called Incoming Payload Signal Absent alarms, can occur on
a split signal if the ports are not in a Y-cable protection group.
Removing an SFP from the
client ports of a card in a Y-cable protection group card causes an IMPROPRMVL
(PPM) alarm. The working and protected port raises the IMPROPRMVL alarm. The
severity on the client ports is changed according to the protection switch
On the OTU2_XP card, when the
10G Ethernet LAN Phy to WAN Phy conversion feature is enabled, Y-cable
protection is not supported on the LAN to WAN interface (ports 1 and 3).
When using fixed DWDM or
tunable XFPs for Y-cable protection, the protection switch time may exceed
The following figure
shows the Y-cable signal flow.
Figure 14. Y-Cable