今天在测试ISIS的时候和别的厂商的居然没法互通，查看数据库发现对方的可达信息都是Extended IP。

R2#sh isis database d
Area GOOD:
IS-IS Level-1 Link State Database:
LSPID                 LSP Seq Num  LSP Checksum  LSP Holdtime      ATT/P/OL
0002.0002.0002.00-00* 0x00000001   0xB75C        1052              0/0/0
  Area Address: 47.0001
  NLPID:        0xCC
  IP Address:   2.0.0.2
  Metric:   10         IP 2.0.0.0 255.255.255.0
  Metric:   10         IP 4.0.0.0 255.255.255.0

IS-IS Level-2 Link State Database:
LSPID                 LSP Seq Num  LSP Checksum  LSP Holdtime      ATT/P/OL
0000.0000.0000.01-00  0x00000005   0xF105        0 (51)            0/0/0
0002.0002.0002.00-00* 0x00000005   0x452A        1064              0/0/0
  Area Address: 47.0001
  NLPID:        0xCC
  IP Address:   2.0.0.2
  Metric:   10         IS 0002.0002.0002.01
  Metric:   10         IP 2.0.0.0 255.255.255.0
  Metric:   10         IP 4.0.0.0 255.255.255.0
0002.0002.0002.01-00* 0x00000001   0xF6B9        1054              0/0/0
  Metric:   0          IS 0002.0002.0002.00
  Metric:   0          IS 0010.0100.1001.00
0010.0100.1001.00-00  0x00000047   0xC13D        1055              0/0/0
  Area Address: 47.0001.00
  Area Address: 49.0000.00
  NLPID:        0xCC
  Hostname:     DUT
  Router ID:    1.1.1.1
  IP Address:   1.1.1.1
  IP Address:   3.0.0.1
  IP Address:   3.0.2.1
  IP Address:   2.0.0.1
  Metric:   10         IS-Extended 0010.0100.1001.02
  Metric:   10         IS-Extended 0002.0002.0002.01
  Metric:   0          IP-Extended 1.1.1.1/32
  Metric:   10         IP-Extended 3.0.0.0/24
  Metric:   10         IP-Extended 3.0.2.0/24
  Metric:   10         IP-Extended 2.0.0.0/24
0010.0100.1001.02-00  0x00000003   0x4A7D        886               0/0/0
  Metric:   0          IS-Extended 0010.0100.1001.00
  Metric:   0          IS-Extended 0010.9400.0005.00
 
估计是使用的宽度量模式，平时自己测试ISIS的时候一般都不配置metric-style，除非要用TE的情况下才要求配置。自己这端不支持宽度量，TLV135和TLV22也就不处理，显然路由是计算不出来的。