Restrictions
These restrictions apply to the 2-Port Gigabit Synchronous Ethernet SPA introduced in Cisco IOS XE Release
3.2:
•
Synchronous SPA features are compatible only with the 2-Port Gigabit Synchronous Ethernet SPA.
•
The maximum theoretical bandwidth of the 2-Port Gigabit Synchronous Ethernet SPA is 2 Gbps full
duplex. The actual performance is limited by the capability of either the host or the jacket card.
•
In a failover scenario, the SPA does not perform any auto switchover to a secondary clock source, even
if the secondary reference is configured on the same SPA. If the primary clock goes down, the platform
explicitly sets the secondary clock as source.
•
The Cisco ASR 1002-X Router was introduced in Release 3.7.0S. This router does not support the 2-Port
Gigabit Synchronous Ethernet SPA.
These restrictions apply to the 1-Port 10-Gigabit Ethernet LAN/WAN PHY SPA introduced in Cisco IOS XE
Release 3.3.0S:
•
If an Ethernet WAN interface is used as a path terminating equipment (PTE) at one end of a SONET
network, only an Ethernet WAN interface can be used for the PTE at the other end of the SONET
network. WAN-PHY SPA will neither interoperate nor terminate on either the packet-over-sonet (PoS)
or the ethernet-over-sonet (EoS) port at the other end.
•
In theory, a 10GBASE-W interface is not intended to interoperate directly with SONET or SDH equipment
because WAN-PHY is not fully compliant with SONET or SDH optical and electrical specifications.
•
For LAN-PHY, the maximum data rate is 10.3125 gigabit per second (Gbps).
•
For WAN-PHY, the maximum data rate is 9.953 gigabit per second (Gbps) (as required by SONET or
SDH).
The Ethernet hardware used for the Cisco Gigabit Ethernet SPA, including the fixed Gigabit Ethernet
ports on the ASR 1000 Series Aggregation Services Routers, can guarantee traffic only at a minimum of
10 bytes Inter-Frame Gap (IFG). If the traffic received is less than 10 bytes IFG, small packet loss can
occur. Under certain conditions, some optical transport gear may transmit packets with 8 bytes IFG.We
recommend to set the link mode to transparent mode on the transport gear, as a work around for the
problem. Another option is to place an intermediate device such as a L2 switch or media transceiver that
can handle the smaller IFG, in between the ASR 1000 Gigabit Ethernet SPA interface and the transport
gear.
Note
Prerequisites for Configuring 1-Port 10-Gigabit Ethernet LAN/WAN PHY SPA
The prerequisites for configuring 1-Port 10-Gigabit Ethernet LAN/WAN PHY SPA are as follows:
•
The minimum Cisco IOS XE Software release image required for 1-Port 10-Gigabit Ethernet LAN/WAN
PHY SPA is Cisco IOS XE Release 3.3.0S or later.
Cisco ASR 1000 Series Aggregation Services Routers SIP and SPA Software Configuration Guide, Cisco IOS
XE Everest 16.5
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Overview of the Ethernet SPAs
Restrictions