Disabling Autonegotiation; Configuring Speed And Duplex - Cisco ASR 1000 Configuration Manual

Chapter 10 Configuring the Ethernet SPAs
For the Gigabit Ethernet interfaces on the Cisco ASR 1000 Series Aggregation Services Routers, flow
control is autonegotiated when autonegotiation is enabled. Autonegotiation is enabled by default.
The following guidelines should be followed regarding autonegotiation:
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Disabling Autonegotiation

Autonegotiation is automatically enabled and can be disabled on the Fast Ethernet and Gigabit Ethernet
interfaces on the Cisco ASR1000-SIP10. During autonegotiation, advertisement for flow control, speed,
and duplex occurs, depending on the media (fiber or copper) in use. If the interface is connected to a link
that has autonegotiation disabled, autonegotiation should either be re-enabled on the other end of the link
or disabled on the Fast Ethernet or Gigabit Ethernet SPA, if possible. Both ends of the link will not come
up properly if only one end of the link has disabled autonegotiation.
Speed and duplex configurations can be advertised using autonegotiation. However, the only values that
are negotiated are:
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From a user's perspective, these settings are not really negotiated, but rather are enabled using
autonegotiation. The SFPs for Gigabit Ethernet SPAS support 1000Base-X, and the IEEE 1000Base-X
standard for fiber does not support negotiation of link speed.
To disable autonegotiation, use the following command in interface configuration mode:
Command
Router(config-if)# no negotiation auto

Configuring Speed and Duplex

When autonegotiation is turned off on Fast Ethernet or the RJ-45 interface in the 2-Port Gigabit Ethernet
SPA, you can manually specify the speed and duplex configuration.
When using the SFP-GE-T, you must configure both the speed and duplex modes.
Note
To configure the speed for a Fast Ethernet or Gigabit Ethernet interface, use the speed command in
interface configuration mode. To return to the default setting, use the no form of this command:
OL-14127-08
If autonegotiation is disabled on one end of a link, it must be disabled on the other end of the link.
If one end of a link has autonegotiation disabled while the other end of the link does not, the link
will not come up properly on both ends.
Autonegotiation is not supported on the 10-Port Gigabit Ethernet SPA on the Cisco
ASR1000-SIP10.
Flow control is enabled by default.
Flow control will be on if autonegotiation is disabled on both ends of the link.
For Fast Ethernet SPAs—100 Mbps for speed and full-duplex mode.
For Gigabit Ethernet SPAs using RJ-45 copper interfaces—1000 Mbps for speed and full-duplex
mode. Link speed is not negotiated when using fiber interfaces.
Cisco ASR 1000 Series Aggregation Services Routers SIP and SPA Software Configuration Guide
Purpose
Disables autonegotiation on Fast Ethernet or Gigabit
Ethernet SPA interfaces on the Cisco ASR1000-SIP10.
No advertisement of flow control occurs.
Configuration Tasks
10-11