1. A method of determining connection information of a link, the link being connected between a first port on a first network element and a second port on a second network element, the first and second network elements being part of a network managed by a network management system, the method comprising the steps of:
enabling Bidirectional Forwarding Detection (BFD) protocol on the first port and the second port;
defining a first BFD discriminator value associated with the first port and a second BFD discriminator value associated with the second port;
populating a link connection profile with the first BFD discriminator value and the second BFD discriminator value; and
notifying the network management system of the link connection profile.
2. The method as claimed in claim 1, wherein the step of populating the connection profile comprises the steps of:
the first network element populating a first BFD signal with the first BFD discriminator value and sending the first BFD signal to the second network element; and
the second network element, on receipt of the first BFD signal, populating a second BFD signal with the first and second BFD discriminator values and sending the second BFD signal to the first network element; and
the first network element populating the link connection profile with the first BFD discriminator value and the second BFD discriminator value.
3. The method as claimed in claim 1, wherein the step of notifying the network management system of the link connection profile comprises the network management system fetching the link connection profile.
4. The method as claimed in claim 1, wherein the step of notifying the network management system of the link connection profile comprises the first network element sending the link connection profile to the network management system in response to receiving the second BFD signal.
5. The method as claimed in claim 1, implemented on demand by the network management system.
6. The method as claimed in claim 1, implemented in response to a change in a topology in the network.
7. A first network element, for a network managed by a network management system, the network including a second network element, the network element comprising:
a first port, for connecting with a second port on the second network element; and
a processor, configured for enabling Bidirectional Forwarding Detection, protocol on the first port, such that a first BFD discriminator value is associated with the first port; wherein
the first port is configured for receiving a second BFD discriminator value associated with the second port, and the processor is configured for populating a link connection profile with the first BFD discriminator value and the second BFD discriminator value, and
the processor is configured for notifying the network management system of the link connection profile.
8. The network element as claimed in claim 7, wherein the first port is configured for sending a first BFD signal to the second port, the first BFD signal comprising the first BFD discriminator value, and for receiving a second BFD signal, the second BFD signal comprising the first BFD discriminator value and the second BFD discriminator value.
9. The network element as claimed in claim 7, wherein the processor is configured for notifying the network management system of the link connection profile in response to receiving the second BFD signal.
10. A network management system, for managing a network including a first network element having a first port, and a second network element having a second port, the network management system comprising:
a communication interface, for communicating with the first port and the second port; and
a processor, configured for sending a message via the communication interface to trigger Bidirectional Forwarding Protocol (BFD) on the first port and second port, wherein
the communication interface is configured to receive a link connection profile, the link connection profile including a first BFD discriminator value associated with the first port and a second BFD discriminator value associated with the second port.
11. The network management system as claimed in claim 10, wherein the processor is configured for fetching the link connection profile via the communication interface.
12. The network management system as claimed in claim 10, wherein the processor is configured for sending a message via the communication interface to trigger BED on the first port and second port in response to a change of topology in the network.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. An optical head device, comprising:
an object lens;
an actuator displacing the object lens;
a mirror which has a reflection plane to bend a direction of a light traveling on an optical axis of the object lens, and, on a back of the reflection plane, a rear surface substantially parallel to the refection plane; and
an optical base which has openings for incorporating the actuator and the mirror, and has a beam at a position opposed to the rear surface of the mirror.
2. The optical head device as set forth in claim 1, wherein a cross-sectional shape of the beam of the optical base has a right triangle having a hypotenuse substantially parallel to the rear surface of the mirror.
3. The optical head device as set forth in claim 1, wherein a cross-sectional shape of the beam of the optical base has a shape which is included in a right triangle having a hypotenuse substantially parallel to the rear surface of the mirror, and at the same time a shape which has a recessed portion on a side of the hypotenuse of the right triangle.
4. The optical head device as set forth in claim 1, wherein the beam of the optical base is positioned apart from the rear surface of the mirror.
5. The optical head device as set forth in claim 1, further comprising, a first light-emitting source to emit a light of a first wavelength which is positioned opposed to the object lens along a reflected light path of the mirror, and a second light-emitting source to emit a light of a second wavelength different from the first wavelength which is positioned apart from the first light-emitting source and is positioned opposed to the object lens along a reflected light path of the mirror.
6. The optical head device as set forth in claim 1, wherein the optical base consists essentially of zinc as material.