3
Cisco IOS XE 3S Release Notes for the Cisco ASR 903 Router
OL-26630-12
Chapter
Limitations and Restrictions
Limitations and Restrictions in Cisco IOS XE Release 3.7(1)aS
There are no changes in limitations and restrictions in Cisco IOS XE Release 3.7(1)aS; the restrictions
from IOS XE Release 3.7(0)S still apply.
Limitations and Restrictions in Cisco IOS XE Release 3.7(0)S
The following limitations apply to the Cisco ASR 903 Router in IOS XE Release 3.7(0)S:
TDM Limitation
•
The
configure replace
command is not supported for TDM interfaces.
ATM IMA Limitation
•
You can create a maximum of 16 IMA groups on each T1/E1 interface module.
Bridge Domain Interface Limitation
•
The
mtu
command is not supported on BDI interfaces; however the
ip mtu
command is supported.
Clocking and Timing Limitation
•
Only a single clocking input source can be configured within each group of eight ports (0-7 and
8-15) on the T1/E1 interface module using the network-clock input-source command.
•
Synchronous Ethernet clock sources are not supported with PTP. Conversely, PTP clock sources are
not supported with synchronous Ethernet. However, you can use hybrid clocking to allow the router
to obtain frequency using Synchronous Ethernet and phase using PTP.
EFP Limitation
•
QinQ is not supported on trunk EFP interfaces.
Equal Cost Multipath Limitation
•
The ASR 903 supports a maximum of 4 Equal Cost Multipath (ECMP) links.
Ethernet IM Limitations
•
The Cisco ASR 903 Router does not support the Facilities Data Link (FDL) on Ethernet interfaces.
•
The Cisco ASR 903 Router does not support the
mac-address
command on Gigabit Ethernet
interface modules.
•
10 Gigabit Ethernet interface modules are not supported in slots 4 and 5.
•
When you install a Gigabit Ethernet IM in the topmost interface module slot (slot 5), the last
interface (interface GigabitEthernet0/5/0) is not operational; the port is reserved for internal
communication.
•
When you configure the copper and SFP Gigabit Ethernet interface modules on a router with
redundant RSPs, the
speed
and
duplex
commands are not visible in interface configuration mode
until you apply a
shutdown
/
no shutdown
to the interface.
•
LACP Fast-Switchover Limitation—Cisco IOS has a default carrier-delay value of 2 seconds. When
an LACP link fails, the router does not perform a switchover until the carrier-delay timer expires.
The
carrier-delay
command helps reduce this value. We recommend that you set a
carrier-delay
value of greater than 0 as this value can result in slower convergence times. We also recommend that
you set an identical
carrier-delay
value on all LACP member links.