With IPHost Network Monitor you can run simple snmp requests against a Cisco device in your network.
pnniLinkCommonPeerGroupId
pnni Link Common Peer Group Id
1.3.6.1.4.1.353.5.4.1.1.9.1.10
For outside links and uplinks, this attribute contains the peer group identifier of the lowest level common Peer Group in the ancestry of the neighboring node and the node within the local switching system. The value of this attribute takes on a value determined by the Hello exchange of hierarchical information that occurs between the two lowest-level border nodes. When the common peer group has not yet been identified, this attribute is set to zero. For horizontal links or when the link type is not yet known, this attribute is set to all zeros.
Back to PNNI-MIB MIB page.
IPHost Network monitor allows you to monitor pnniLinkCommonPeerGroupId on Cisco device via the SNMP protocol. Download IPHost Network Monitor (500 monitors for 30 days, 50 monitors free forever) to start monitoring Cisco optical switches right now.