Hi, Juniper routers support enabling(this is the default setting) and disabling auto-negotiation both on 1000BASE-T(copper) and 1000BASE-X(optical) interfaces. Auto-negotiation on copper ports makes sense because copper ports(for example on tri-rate DPC's on MX960) support 10BASE-T and 100BASE-TX modes besides 1000BASE-T, 1000BASE-T supports both full- and half-duplex modes according to IEEE 802.3z and master/slave relationship between two ports needs to be determined for negotiating the clock settings. However, what is negotiated between two directly connected 1000BASE-X ports when auto-negotiation is enabled on both ports? I mean optical transceivers rated to 1Gbps do not support backward compatibility to lower speeds and are there optical transceivers out there that support half-duplex mode(it's supported according to IEEE 802.3 22.2.4.4.2)? In a nutshell, why is auto-negotiation needed on 1000BASE-X ports?
regards, Martin _______________________________________________ juniper-nsp mailing list [email protected] https://puck.nether.net/mailman/listinfo/juniper-nsp
