Traffic Engineering (TE)¶

Beyond the basic IGP cost, OSPF and IS-IS can carry Traffic Engineering attributes — bandwidth, a separate TE metric, and administrative groups/affinities. Topolograph parses these and makes them available for richer visualization and filtering, for both OSPF and IS-IS.

TE is optional

Your graph builds fine from plain LSA 1/2/5 (OSPF) or the standard IS-IS LSDB. TE data is extra — turn it on when you need capacity-aware analysis.

What Topolograph parses¶

Attribute	API/SDK name	Meaning
TE default metric	`temetric`	TE-specific link metric (independent of IGP cost)
Administrative group	`admin_group`	Affinity / color / resource class
Maximum link bandwidth	`max_link_bw`	Physical link capacity
Maximum reservable bandwidth	`max_rsrv_link_bw`	Bandwidth available for reservation
Unreserved bandwidth (per priority)	`unreserved_bw_0` … `unreserved_bw_7`	Remaining bandwidth at each of the 8 TE priorities

The same attribute names are used regardless of whether the data came from OSPF or IS-IS.

How to feed TE data in¶

OSPF — text fileIS-IS — text fileOSPF / IS-IS — BGP-LS

Include show ip ospf database opaque-area in the same upload file as your router/network/external LSDB. Type-10 (opaque-area) LSAs carry the TE data; the rest of the graph is built from LSA 1, 2 and 5 as usual.

Text file upload

TE attributes come straight from the IS-IS LSDB when you use the standard detailed commands (e.g. FRR show isis database detail). No extra command is required beyond your normal IS-IS capture.

BGP-LS carries TE attributes natively — admin group, maximum and reservable bandwidth, unreserved bandwidth, and the TE default metric — with no opaque-LSA trick needed. TE updates stream into the monitoring view live.

BGP-LS session

When TE data arrives over BGP-LS, the monitoring page shows the link attributes as updates come in:

TE link attributes on the monitoring page via BGP-LS

Filtering links by TE attributes¶

Once a diagram has TE data, you can query edges by any TE attribute using the range operators __gt, __lt, __gte, __lte — handy for finding links that violate (or satisfy) a TE constraint. With the Python SDK:

# Links with TE metric >= 100
edges = graph.edges_list(temetric__gte=100)

# Links with unreserved bandwidth at priority 0 below 1 Gbps
edges = graph.edges_list(unreserved_bw_0__lt=1e9)

# Links between two nodes with max link bandwidth above 10 Gbps
edges = graph.edges_list(src_node="1.1.1.1", dst_node="2.2.2.2", max_link_bw__gt=1e10)

The same filtering is available through the diagram edges REST API.

IS-IS specifics¶

IS-IS TE relies on wide metrics (Extended IS/IP Reachability, TLVs 22/135) and supports IPv6 reachability (TLV 236). Vendor support for the relevant TLVs is summarized on the Supported Vendors page.

Monitoring TE changes¶

When a Watcher is connected, changes to TE attributes are captured as events alongside cost and adjacency changes — see the te_log views in ELK / Kibana and the IS-IS Watcher page.