Determining Asymmetries in a Communication Network

A first network node of a communication network, the network node configured to measure asymmetry in transmission delay due to the use of different wavelengths on one or more links which connect a first node to a second node of a communication network, the first network node comprising:

• an input port coupled to the one or more link;
• an output port coupled to the one or more link;
• and
• wherein the first network node is operable to:
• determine a forward transmission delay for a forward direction from the first node to the second node using a first wavelength, and
• determine a reverse transmission delay for a reverse direction from the second node to the first node using a second wavelength, wherein the second wavelength is different from the first wavelength;
• and
• determine an asymmetry due to the use of different wavelengths in transmission delay between the forward delay and reverse delay from a calculation of a group delay applicable to the different wavelengths used in the forward direction and in the reverse direction.

A computer-readable storage medium, having stored thereon a computer program executable by at least one processor to cause the at least one processor to:

• determine a forward transmission delay for a forward direction from the first node to the second node using a first wavelength, and
• determine a reverse transmission delay for a reverse direction from the second node to the first node using a second wavelength, wherein the second wavelength is different from the first wavelength;
• and
• determine an asymmetry due to the use of different wavelengths in transmission delay between the forward delay and reverse delay from a calculation of a group delay applicable to the different wavelengths used in the forward direction and in the reverse direction.