IS-IS(ISO 10589) is Integrated System to Integrated System which was initially designed by DEC for OSI then tuned to work for TCP/IP protocol by the IETF in RFC 1195. In other words we can say a robust protocol which now supports the both ip as well as CLNP applications. It is a link state routing protocol and uses the same DIJKSTRA algorithm as being used by OSPF (Open Shortest Path First) to calculate the path cost.
IS-IS maintains three types of tables:-
1. Neighbor Table
2. Routing Table
3. Topology Table
Address Format Used By IS-IS
OSI uses connectionless Network Service aka CLNS which is equivalent to IP in TCP/IP. CLNP assigning addresses to a router called Network Service Access Point(NSAP) addresses or Network Entity Title(NET) addresses. IS-IS uses a one address per node. Net addresses can be up to 20 bytes in length. CISCO implementation of NET address tells about area, system id and NSAP selector.
Types Of Router
1. Level 1 (L1) – It maintains the topology database of its own area.
2. Level 2 router consider as backbone router.
3. Level 1-2 routers are interfaces between the Level 1 and Level 2.
The main advantage of using IS-IS because of it’s TLV (Type/Length/Value) which makes it unique from legacy OSPF. It is a hearsay that support of IPv6 in OSPF requires lot of modification from it’s root but the presence of TLV in IS-IS helped it to support IPv6 with no more changes.
Friday, February 26, 2010
Basics Of IS-IS
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3 comments:
We phase issue when we make l2 ckt with VFI in 7604.
End-to-End VC comming up, but not able to ping end to end.
Router A configuration :
l2 vfi TEST autodiscovery
vpn id 3000
interface Vlan3000
description 'TEST_L2_CKT'
ip address 13.13.13.50 255.255.255.252
xconnect vfi TEST
A-RTR#sh mpls l2transport vc details
A-RTR#sh mpls l2transport vc 3000 detail
Local interface: VFI TEST VFI up
Interworking type is Ethernet
Destination address: 10.134.254.36, VC ID: 3000, VC status: up
Output interface: none, imposed label stack {1055 880}
Preferred path: not configured
Default path: active
Next hop: Invalid ADDR
Create time: 03:35:45, last status change time: 01:25:07
Signaling protocol: LDP, peer 10.134.254.36:0 up
Targeted Hello: 10.135.254.22(LDP Id) -> 10.134.254.36
Status TLV support (local/remote) : enabled/supported
Label/status state machine : established, LruRru
Last local dataplane status rcvd: no fault
Last local SSS circuit status rcvd: no fault
Last local SSS circuit status sent: no fault
Last local LDP TLV status sent: no fault
Last remote LDP TLV status rcvd: no fault
MPLS VC labels: local 1076, remote 880
AGI: type 1, len 8, 000A FDE8 0000 0BB8
Local AII: type 1, len 4, 0A87 FE16 (10.135.254.22)
Remote AII: type 1, len 4, 0A86 FE24 (10.134.254.36)
Group ID: local n/a, remote n/a
MTU: local 1500, remote 1500
Remote interface description:
Sequencing: receive disabled, send disabled
VC statistics:
packet totals: receive 56, send 0
byte totals: receive 3641, send 0
packet drops: receive 0, seq error 0, send 0
========================
Router B :
l2 vfi TEST autodiscovery
vpn id 3000
interface Vlan3000
description 'TEST_L2_CKT'
ip address 13.13.13.49 255.255.255.252
xconnect vfi TEST
B-RTR#sh mpls l2transport vc 3000 detail
Local interface: VFI TEST VFI up
Interworking type is Ethernet
Destination address: 10.134.254.36, VC ID: 3000, VC status: up
Output interface: none, imposed label stack {1055 880}
Preferred path: not configured
Default path: active
Next hop: Invalid ADDR
Create time: 03:35:45, last status change time: 01:25:07
Signaling protocol: LDP, peer 10.134.254.36:0 up
Targeted Hello: 10.135.254.22(LDP Id) -> 10.134.254.36
Status TLV support (local/remote) : enabled/supported
Label/status state machine : established, LruRru
Last local dataplane status rcvd: no fault
Last local SSS circuit status rcvd: no fault
Last local SSS circuit status sent: no fault
Last local LDP TLV status sent: no fault
Last remote LDP TLV status rcvd: no fault
MPLS VC labels: local 1076, remote 880
AGI: type 1, len 8, 000A FDE8 0000 0BB8
Local AII: type 1, len 4, 0A87 FE16 (10.135.254.22)
Remote AII: type 1, len 4, 0A86 FE24 (10.134.254.36)
Group ID: local n/a, remote n/a
MTU: local 1500, remote 1500
Remote interface description:
Sequencing: receive disabled, send disabled
VC statistics:
packet totals: receive 56, send 0
byte totals: receive 3641, send 0
packet drops: receive 0, seq error 0, send 0
====================
A side next hope showing point-to-point and B end it's shows Invalid ADDR
PLS SUGGEST.
Just check next hop is showing invalid address.
Basics Of IS-IS
i like this post,thanx
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