Cisco ASR 903 Release Notes page 85

Chapter
Equal Cost Multipath Limitation
The ASR 903 supports a maximum of 4 Equal Cost Multipath (ECMP) links.
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Ethernet IM Limitations
The Cisco ASR 903 Router does not support the Facilities Data Link (FDL) on Ethernet interfaces.
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The Cisco ASR 903 Router does not support the mac-address command on Gigabit Ethernet
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interface modules.
10 Gigabit Ethernet interface modules are not supported in slots 4 and 5.
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When you install a Gigabit Ethernet IM in the topmost interface module slot (slot 5), the last
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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
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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.
MLPPP Limitations
The following limitations apply when using MLPPP on the Cisco ASR 903 Router:
All links in an MLPPP bundle must be on the same interface module.
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All links in an MLPPP bundle must be of the same bandwidth.
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The Cisco ASR 903 Router supports a maximum of 8 links per bundle
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To change the MLPPP bundle fragmentation mode between enabled and disabled, perform a
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shutdown/no shutdown on the bundle.
LFI is not supported
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Multiclass MLP is not supported
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The Cisco ASR 903 Router supports MLPPP statistics with the following limitations:
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If you increase the maximum transmission unit (MTU) size on an MLPPP interface to a value higher
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than the maximum received reconstructed unit (MRRU) value on the peer interface, this can bring
the MLPPP tunnel down. To restore the tunnel, perform a shutdown/no shutdown on the interface.
MPLS VPN Limitation
MPLS VPN (L3VPN) Fragmentation does not function properly if an access interface has a higher
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MTU value than a core interface. To ensure that fragmentation functions correctly, configure the
core interface MTU with a value that exceeds the access interface MTU and relevant headers.
OC-3 IM Limitations
SDH framing mode is supported; SONET is not supported.
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The optical interface module is designed for OC-3 and OC-12 traffic, but OC-12 functionality is not
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currently supported.
OL-26630-08
Packet counters on the bundle display the number of fragments rather than packets.
Control packets are accounted on the bundle.
Cisco IOS XE 3S Release Notes for the Cisco ASR 903 Router
Limitations and Restrictions
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