Tuesday, 25 December 2018

                             FabricPath



Today’s topic is Fabricpath and Conversational MAC address learning. We will also discuss how Fabricpath overcomes the limitation of traditional Spanning Tree Protocol (STP).
To start with, let me first point out the limitations of STP and why the need of new technology. (Assuming you already have basic understanding of how STP works.)
Spanning Tree Protocol:
  • STP is a Layer 2 protocol running on Bridges / Switches and is specified as IEEE 802.1D.
  • It ensures that there are no loops when you have redundant paths in the network.
  • However in the process, one of the link is blocked and does not participate in forwarding until unless active link has failed. So one link is not even being utilized and cant be used for ECMP even if one link is congested.
  • Apart from ECMP disability, poor convergence and unnecessary MAC flooding are also the disadvantages of STP.
  • As every link counts in the Data Center environment and cannot afford getting one of the link being overutilized when another link is lying down without any traffic.
Fabricpath:
Fabricpath is a Layer 2 routing also known as MAC-in-MAC routing. IS-IS is run in the background to maintain the control plane for Unicast and BUM (Broadcast, unknown unicast and multicast) traffic.
** You must have an F Series module installed in your Nexus 7000 Series chassis in order to run FabricPath and conversational learning.
FabricPath Terminology
Classic Ethernet – By default Vlan mode is CE, until unless fabricpath is not configured. It runs traditional STP
Leaf Switch – This is the edge switch that connects to the CE domain, everything connects to the leaf switches.
Spine Switch – This is the backbone switch, all ports are fabricpath ports.
FabricPath Core Ports – Ports that connects  the leaf switches to the spine or the spine switches to each other.
CE Edge Ports – Ports that connect the CE domain to the Leaf switches.
The FabricPath feature provides the following:
  1. Allows Layer 2 multipathing in the FabricPath network.
  2. Provides built-in loop prevention and mitigation with no need to use the Spanning Tree Protocol (STP).
  3. Provides a single control plane for unknown unicast, unicast, broadcast, and multicast traffic.
  4. Enhances mobility and virtualization in the FabricPath network.
Working of fabricpath:
  • When a frame enters the FabricPath network from a Classical Ethernet (CE) network, the ingress interface encapsulate the frame with a FabricPath header.
  • The system builds paths, called trees, through the FabricPath network and assigns a forwarding tag (FTag) by flow to all the traffic in the FabricPath network.
  • When the frame leaves the FabricPath network to go to a CE network, the egress interface decapsulates the frame and leaves the regular CE header.
  • The underlying protocol is IS-IS which is used to advertise the routes from Leaf to Leaf via Spines. This is completely different from Layer-3 ISIS routing protocol. No configuration is required to run Layer-2 ISIS. It is automatically triggered once fabricpath is configured on the interface.
Conversational MAC address learning:
The type of MAC address learning (Traditional or Conversational) is dependent on the VLAN configuration.Each interface only learn those MAC address for interested hosts, rather all the addresses in the domain.If a switch receives a frame and that destination address is known to the switch, in that case only it will learn the source MAC address and store it in table.This saves the CAM resources and optimizes the control plane.
Topology used:
Topology
Steps:
1. Activate the feature fabricpath on all the devices:
Spine-1(config)# install feature-set fabricpath
Spine-1(config)# feature-set fabricpath
Spine-2(config)#     install feature-set fabricpath
Spine-2(config)#     feature-set fabricpath
Leaf-1(config)#     install feature-set fabricpath
Leaf-1(config)#     feature-set fabricpath
Leaf-2(config)#     install feature-set fabricpath
Leaf-2(config)#     feature-set fabricpath
2. Once the fabricpath is installed, auto generated switch id is assigned to the device. This is a 12-bit address dynamically assigned via DRAP (Dynamic Resource Allocation Protocol), which is used for identifying the switch in the FabricPath domain.
Spine-1(config)# show fabricpath switch-id local
Switch-Id: 2316System-Id: 5001.0001.002f
Spine-2(config)# show fabricpath switch-id local
Switch-Id: 2544System-Id: 5001.0002.002f
Leaf-1(config)# show fabricpath switch-id local
Switch-Id: 267System-Id: 5001.0003.002f
Leaf-2(config)# show fabricpath switch-id local
Switch-Id: 1196System-Id: 5001.0004.002f
The system-id is the MAC address of the switch. In order to easily identify the switch in network, we generally do manual assignment for the switch-id.
** Assigned Switch-Id 1 to Spine-1 **
Spine-1(config)# fabricpath switch-id 1Spine-1(config)# show fabricpath switch-id
FABRICPATH SWITCH-ID TABLE
Legend: ‘*’ – this system
‘[E]’ – local Emulated Switch-id
‘[A]’ – local Anycast Switch-id
Total Switch-ids: 1
=======================================================
SWITCH-ID      SYSTEM-ID       FLAGS         STATE    STATIC  EMULATED/ANYCAST
————–+—————-+————+———–+——————–
*   1           5001.0001.002f    Primary     Confirmed Yes     No       >>>>> * means this is the local switch
Spine-2(config)# fabricpath switch-id 2
Leaf-1(config)# fabricpath switch-id 3
Leaf-2(config)# fabricpath switch-id 4
3. Configure interfaces to work in fabricpath switchport mode. Once you enable this, ISIS will automatically run between devices and we can see adjacencies being formed.
Spine-1# sh run int e2/1-2
interface Ethernet2/1
switchport
switchport mode fabricpathno shutdown
interface Ethernet2/2
switchport
switchport mode fabricpath
no shutdown
Spine-1# sh run int e2/4
interface Ethernet2/4
switchport
switchport mode fabricpath
no shutdown
Spine-1# show fabricpath isis adjacency
Fabricpath IS-IS domain: default Fabricpath IS-IS adjacency database:
System ID       SNPA            Level  State  Hold Time  Interface
Leaf-1          N/A             1      UP     00:00:25   Ethernet2/1
Leaf-2          N/A             1      UP     00:00:24   Ethernet2/2
Spine-2         N/A             1      UP     00:00:25   Ethernet2/4
Spine-2# show fabricpath isis adjacency
Fabricpath IS-IS domain: default Fabricpath IS-IS adjacency database:
System ID       SNPA            Level  State  Hold Time  Interface
Leaf-1          N/A             1      UP     00:00:22   Ethernet2/1
Leaf-2          N/A             1      UP     00:00:28   Ethernet2/2
Spine-1         N/A             1      UP     00:00:25   Ethernet2/4
Leaf-1# show fabricpath isis adjacency
Fabricpath IS-IS domain: default Fabricpath IS-IS adjacency database:
System ID       SNPA            Level  State  Hold Time  Interface
Spine-1         N/A             1      UP     00:00:25   Ethernet2/1
Spine-2         N/A             1      UP     00:00:27   Ethernet2/2
Leaf-2          N/A             1      UP     00:00:24   Ethernet2/5
Leaf-2# show fabricpath isis adjacency
Fabricpath IS-IS domain: default Fabricpath IS-IS adjacency database:
System ID       SNPA            Level  State  Hold Time  Interface
Spine-1         N/A             1      UP     00:00:29   Ethernet2/1
Spine-2         N/A             1      UP     00:00:31   Ethernet2/2
Leaf-1          N/A             1      UP     00:00:25   Ethernet2/5
Ports

4. Now as the adjacency is formed, we can see the neighbor’s switch-id as well:
Spine-1# show fabricpath switch-id
FABRICPATH SWITCH-ID TABLE
Legend: ‘*’ – this system
‘[E]’ – local Emulated Switch-id
‘[A]’ – local Anycast Switch-id
Total Switch-ids: 4
==========================================================
SWITCH-ID      SYSTEM-ID       FLAGS         STATE    STATIC  EMULATED/ANYCAST
————–+—————-+————+———–+——————–
*   1           5001.0001.002f    Primary     Confirmed Yes     No
2           5001.0002.002f    Primary     Confirmed Yes     No
3           5001.0003.002f    Primary     Confirmed Yes     No
4           5001.0004.002f    Primary     Confirmed Yes     No
Spine-2# show fabricpath switch-id
1           5001.0001.002f    Primary     Confirmed Yes     No
*   2           5001.0002.002f    Primary     Confirmed Yes     No
3           5001.0003.002f    Primary     Confirmed Yes     No
4           5001.0004.002f    Primary     Confirmed Yes     No
Leaf-1# show fabricpath switch-id
1           5001.0001.002f    Primary     Confirmed Yes     No
2           5001.0002.002f    Primary     Confirmed Yes     No
*   3           5001.0003.002f    Primary     Confirmed Yes     No
4           5001.0004.002f    Primary     Confirmed Yes     No
Leaf-2# show fabricpath switch-id
1           5001.0001.002f    Primary     Confirmed Yes     No
2           5001.0002.002f    Primary     Confirmed Yes     No
3           5001.0003.002f    Primary     Confirmed Yes     No
*   4           5001.0004.002f    Primary     Confirmed Yes     No
5. Now as all the interfaces are running fabricpath, we see that traditional STP does not exist on switches.
Spine-1# show spanning-tree
No spanning tree instance exists.
Spine-1#
Spine-2# show spanning-tree
No spanning tree instance exists.
Spine-2#
Leaf-1# show spanning-tree
No spanning tree instance exists.
Leaf-1#
Leaf-2# show spanning-tree
No spanning tree instance exists.
Leaf-2#

6. Configure VLAN on all boxes to work in fabricpath mode.
Spine-1(config)# vlan 10,20
Spine-1(config-vlan)# mode fabricpath
Spine-1# show vlan
VLAN Name                             Status    Ports
— ——————————– ——— ——————————-
1    default                          active
10   VLAN0010                         active    Eth2/1, Eth2/2, Eth2/4
20   VLAN0020                         active    Eth2/1, Eth2/2, Eth2/4
VLAN Type         Vlan-mode
—- —–        ———-
1    enet         CE
10   enet         FABRICPATH20   enet         FABRICPATH
Routing in Fabricpath:
Spine-1# show fabricpath route
FabricPath Unicast Route Table
‘a/b/c’ denotes ftag/switch-id/subswitch-id‘[x/y]’ denotes [admin distance/metric]
ftag 0 is local ftag
subswitch-id 0 is default subswitch-id
FabricPath Unicast Route Table for Topology-Default
0/1/0, number of next-hops: 0
via —- , [60/0], 0 day/s 02:41:19, local
1/2/0, number of next-hops: 1 >>>>>>>>>>>>>>>>>>>. Ftag-1, SwitchId – 2, SubSwitchId-0via Eth2/4, [115/400], 0 day/s 00:23:25, isis_fabricpath-default
1/3/0, number of next-hops: 1
via Eth2/1, [115/400], 0 day/s 00:24:32, isis_fabricpath-default
1/4/0, number of next-hops: 1
via Eth2/2, [115/400], 0 day/s 00:12:05, isis_fabricpath-default
Spine-2# show fabricpath route
0/2/0, number of next-hops: 0
via —- , [60/0], 0 day/s 02:40:53, local
1/1/0, number of next-hops: 1
via Eth2/4, [115/400], 0 day/s 01:12:52, isis_fabricpath-default
1/3/0, number of next-hops: 1
via Eth2/1, [115/400], 0 day/s 00:24:11, isis_fabricpath-default
1/4/0, number of next-hops: 1
via Eth2/2, [115/400], 0 day/s 00:11:46, isis_fabricpath-default

Leaf-1# show fabricpath route
0/3/0, number of next-hops: 0
via —- , [60/0], 0 day/s 00:27:41, local
1/1/0, number of next-hops: 1
via Eth2/1, [115/400], 0 day/s 00:23:39, isis_fabricpath-default
1/2/0, number of next-hops: 1
via Eth2/2, [115/400], 0 day/s 00:22:48, isis_fabricpath-default
1/4/0, number of next-hops: 2
via Eth2/1, [115/800], 0 day/s 00:11:29, isis_fabricpath-default
via Eth2/2, [115/800], 0 day/s 00:11:29, isis_fabricpath-default
Leaf-2# show fabricpath route
0/4/0, number of next-hops: 0
via —- , [60/0], 0 day/s 00:11:43, local
1/1/0, number of next-hops: 1
via Eth2/1, [115/400], 0 day/s 00:10:52, isis_fabricpath-default
1/2/0, number of next-hops: 1
via Eth2/2, [115/400], 0 day/s 00:10:52, isis_fabricpath-default
1/3/0, number of next-hops: 2
via Eth2/1, [115/800], 0 day/s 00:10:52, isis_fabricpath-default
via Eth2/2, [115/800], 0 day/s 00:10:52, isis_fabricpath-default
ISIS topology:
Spine-1# show fabricpath isis topology summary
FabricPath IS-IS Topology Summary
Fabricpath IS-IS domain: default
MT-0
Configured interfaces:  Ethernet2/1  Ethernet2/2  Ethernet2/4
Max number of trees: 2  Number of trees supported: 2
Tree id: 1, ftag: 1, root system: 5001.0004.002f, 4
Tree id: 2, ftag: 2, root system: 5001.0003.002f, 3
Ftag Proxy Root: 5001.0004.002f
Spine-2# show fabricpath isis topology summary

MT-0
Configured interfaces:  Ethernet2/1  Ethernet2/2  Ethernet2/4
Max number of trees: 2  Number of trees supported: 2
Tree id: 1, ftag: 1, root system: 5001.0004.002f, 4
Tree id: 2, ftag: 2, root system: 5001.0003.002f, 3
Ftag Proxy Root: 5001.0004.002f
Leaf-1# show fabricpath isis topology summary

MT-0
Configured interfaces:  Ethernet2/1  Ethernet2/2
Max number of trees: 2  Number of trees supported: 2
Tree id: 1, ftag: 1, root system: 5001.0004.002f, 4
Tree id: 2, ftag: 2, root system: 5001.0003.002f, 3
Ftag Proxy Root: 5001.0004.002f
Leaf-2# show fabricpath isis topology summary

MT-0
Configured interfaces:  Ethernet2/1  Ethernet2/2
Max number of trees: 2  Number of trees supported: 2
Tree id: 1, ftag: 1, root system: 5001.0004.002f, 4
Tree id: 2, ftag: 2, root system: 5001.0003.002f, 3
Ftag Proxy Root: 5001.0004.002f
FP switches share the common bridge id 32778 c84c.75fa.6000.  Leafs must have same priority if connected to same CE segment. Mismatch priority can result in root inconsistent. STP is not propagated towards Fabricpath network.
Leaf-1# show spanning-tree vlan 10 root
Root  Hello Max Fwd
Vlan                   Root ID          Cost  Time  Age Dly  Root Port
—————- ——————– ——- —– — —  —————-
VLAN0010         32778 c84c.75fa.6000       0    2   20  15  This bridge is root
Leaf-1# show spanning-tree vlan 20 root
Root  Hello Max Fwd
Vlan                   Root ID          Cost  Time  Age Dly  Root Port
—————- ——————– ——- —– — —  —————-
VLAN0020         32788 c84c.75fa.6000       0    2   20  15  This bridge is root
Leaf-2# show spanning-tree vlan 10 root
Root Hello Max Fwd
Vlan Root ID Cost Time Age Dly Root Port
—————- ——————– ——- —– — — —————-
VLAN0010 32778 c84c.75fa.6000 0 2 20 15 This bridge is root
Leaf-2# show spanning-tree vlan 20 root
Root Hello Max Fwd
Vlan Root ID Cost Time Age Dly Root Port
—————- ——————– ——- —– — — —————-
VLAN0020 32788 c84c.75fa.6000 0 2 20 15 This bridge is root
Leaf-2#
MAC Address Table:
Leaf-2# show system internal l2fwder mac/Show mac address-table
Stl Static   BD       MAC-Address   FTAG.Sid/L2_Intf  GM  Type      Age
—|——|—–|——————|—————-|—|—–|———|
0      0    20  aa:bb:cc:00:71:10             1, 3   0     0  00:00:50* —————–> 1 is ftag and 3 is switch-id0      0    20  aa:bb:cc:00:51:10           Eth2/4   0     0  00:09:27*
0      0    10  aa:bb:cc:00:71:00           Eth2/3   0     0  00:24:54*
0      1    20  50:01:00:04:00:2f         sup-eth1   1     0  00:24:25
0      1    10  50:01:00:04:00:2f         sup-eth1   1     0  00:24:31
Now it will check the routing table on where to forward this switch-id:
Leaf-2# show fabricpath route switchid 3
FabricPath Unicast Route Table
‘a/b/c’ denotes ftag/switch-id/subswitch-id
‘[x/y]’ denotes [admin distance/metric]
ftag 0 is local ftag
subswitch-id 0 is default subswitch-id
FabricPath Unicast Route Table for Topology-Default
1/3/0, number of next-hops: 2
via Eth2/1, [115/800], 0 day/s 00:27:03, isis_fabricpath-default
via Eth2/2, [115/800], 0 day/s 00:27:03, isis_fabricpath-default
Fabricpath Multidestination Tree:
Ftag is used for Multidestination trees . Each tree is assigned a network-wide identity, known as an FTAG.
The first tree is used to handle broadcast and unknown unicasts, the second tree is used to handle multicast traffic.
Leaf-2# show fabricpath isis topology summary
FabricPath IS-IS Topology Summary
Fabricpath IS-IS domain: default
MT-0
Configured interfaces:  Ethernet2/1  Ethernet2/2
Max number of trees: 2  Number of trees supported: 2
Tree id: 1, ftag: 1, root system: 5001.0004.002f, 4
Tree id: 2, ftag: 2, root system: 5001.0003.002f, 3
Ftag Proxy Root: 5001.0004.002f
Tree 1 = FTAG 1 = Broadcast and unknown unicastTree 2 = FTAG 2 = Multicast
From the output above, we can see that SID 4 has been chosen as the root for Tree 1, and SID 3 has been chosen as the root for Tree 2.
So, Spine-1 is the root for Broadcast and unknown unicast. Spine-2 is the root for Multicast traffic.
Once the frame is received at CE port, it checks the destination MAC address and based on the type of traffic, frame is encapsulated in Fabricpath Header with Outer Source Address (OSA) as Source Switch Id and Outer Destination Address (ODA) as Destination Switch ID. The Ether type is used as 0x8903 to identify the Fabricpath protocol. Here, the OSA will be 12-bit switch ID for Leaf-2 which is 4 and ODA will be switch ID 3.
FP ping
The root is chosen automatically just like STP:
1. Highest root priority – 8-bit value between 0-255 (Default is 64)
2. Highest System-ID – 48-bit VDC MAC address
3. Highest Switch-ID – 12-bit SID
For Leaf-2, Leaf-2 itself is the root for Tree 1 and the second highest root is the Leaf-1 for Tree 2.
To make the Spine-1 as the root for Tree 1 and Spine 2 as the root for Tree 2, we can change the priority:
Spine-1(config)# fabricpath domain default
Spine-1(config-fabricpath-isis)# root-priority 255
Spine-2(config)# fabricpath domain default
Spine-2(config-fabricpath-isis)# root-priority 254
Leaf-2# show fabricpath isis topology summary
FabricPath IS-IS Topology Summary
Fabricpath IS-IS domain: default
MT-0
Configured interfaces:  Ethernet2/1  Ethernet2/2
Max number of trees: 2  Number of trees supported: 2
Tree id: 1, ftag: 1, root system: 5001.0001.002f, 1 —> Spine-1 is the root for Tree-1 nowTree id: 2, ftag: 2, root system: 5001.0002.002f, 2—-> Spine-2 is the root for Tree-2 nowFtag Proxy Root: 5001.0001.002f
mdst tree
“show fabricpath isis trees” shows the metric in respect to the root.
Leaf-2# show fabricpath isis trees
Fabricpath IS-IS domain: default
Note: The metric mentioned for multidestination tree is from the root of that tree to that switch-id
*:directly connected neighbor or link
P:Physical switch-id, E:Emulated, A:Anycast
MT-0
Topology 0, Tree 1, Swid routing table
1, L1
via Ethernet2/1, metric 0 —->Root is directly connected on this link for Tree-12, L1
via Ethernet2/1, metric 400
3, L1
via Ethernet2/1, metric 400
Topology 0, Tree 2, Swid routing table
1, L1
via Ethernet2/2, metric 400
2, L1
 via Ethernet2/2, metric 0 ——-> Root is directly connected on this link for Tree-23, L1
via Ethernet2/2, metric 400
Traffic Engineering in FabricPath:
– Currently, we are doing multipathing to reach Leaf-1 from Leaf-2 and vice-versa.
Leaf-2# show fabricpath route switchid 3
1/3/0, number of next-hops: 2
via Eth2/1, [115/800], 0 day/s 01:06:21, isis_fabricpath-default
via Eth2/2, [115/800], 0 day/s 01:06:21, isis_fabricpath-default
– 115 is the ISIS Admin Distance and 800 is the metric (400 per link from Leaf-Spine-Leaf).
– In order to prefer only one path, we can increase the ISIS metric on one link.
Leaf-2(config)# int e2/2
Leaf-2(config-if)# fabricpath isis metric 500
Leaf-2# show fabricpath route switchid 3
1/3/0, number of next-hops: 1
via Eth2/1, [115/800], 0 day/s 01:09:11, isis_fabricpath-default

Fabricpath ECMP:
– We can check the mroute table for each ftag and see the outgoing interface. It is E2/1 for Ftag-1 and E2/2 for Ftag-2.
Leaf-2# show fabricpath mroute ftag 1
(ftag/1, vlan/10, *, *), Flood, uptime: 01:11:48, isis
Outgoing interface list: (count: 3)
Interface Ethernet2/1,   Switch-id 1, uptime: 01:11:52, isis
Interface Ethernet2/1,   Switch-id 2, uptime: 00:11:10, isis
Interface Ethernet2/1,   Switch-id 3, uptime: 01:11:52, isis
(ftag/1, vlan/20, *, *), Flood, uptime: 01:11:48, isis
Outgoing interface list: (count: 3)
Interface Ethernet2/1,   Switch-id 1, uptime: 01:11:52, isis
Interface Ethernet2/1,   Switch-id 2, uptime: 00:11:10, isis
Interface Ethernet2/1,   Switch-id 3, uptime: 01:11:52, isis
Leaf-2# show fabricpath mroute ftag 2
(ftag/2, vlan/10, *, *), Flood, uptime: 01:12:14, isis
Outgoing interface list: (count: 3)
Interface Ethernet2/2,   Switch-id 1, uptime: 00:11:13, isis
Interface Ethernet2/2,   Switch-id 2, uptime: 01:12:18, isis
Interface Ethernet2/2,   Switch-id 3, uptime: 01:12:18, isis
(ftag/2, vlan/20, *, *), Flood, uptime: 01:12:14, isis
Outgoing interface list: (count: 3)
Interface Ethernet2/2,   Switch-id 1, uptime: 00:11:13, isis
Interface Ethernet2/2,   Switch-id 2, uptime: 01:12:18, isis
Interface Ethernet2/2,   Switch-id 3, uptime: 01:12:18, isis
– Verify the ECMP method being used.
Leaf-2# show fabricpath load-balance
ECMP load-balancing configuration:
L3/L4 Preference: Mixed
Hash Control: Symmetric
Rotate amount: 12 bytes
Use VLAN: TRUE
Ftag load-balancing configuration:
Hash Control: Symmetric
Rotate amount: 12 bytes
Use VLAN: TRUE
Leaf-2(config)# sh run all | i “fabricpath load-balance”
fabricpath load-balance symmetric
fabricpath load-balance unicast mixed rotate-amount 0xc
fabricpath load-balance multicast rotate-amount 0xc
Leaf-2(config)#

– ECMP methods available:
Leaf-2(config)# fabricpath load-balance unicast ?
include-vlan   Use hardware translation of vlan/vni
layer3         Only Layer-3 parameters considered
layer4         Only Layer-4 parameters considered
mixed          Mix of Layer-3 and Layer-4 paramaters (default)
rotate-amount  Rotate amount for hash string
– To check which interface will be selected based on the Source and Destination, use below command:
Leaf-2# show fabricpath load-balance unicast forwarding-path ftag 1 switchid 3 flow-type l3 src-ip 10.0.0.253 dst-ip 10.0.0.225 vlan 10 module 2
This flow selects interface Eth2/1
Fabricpath Authentication: There are two types of Authentication being used in Fabricpath:
– Fabricpath Interface Authentication, which is basically used for Hello
– Fabricpath domain Authentication which is intended for ISIS LSPs
1. Interface Authentication: Lets configure Authentication between Spine-1 and Spine-2 on interface E2/4.
ISIS- hellos
Spine-1(config)# key chain Spine-1
Spine-1(config-keychain)# key 1
Spine-1(config-keychain-key)# key-string Spine-1
Spine-1(config)# int e2/4
Spine-1(config-if)# fabricpath isis authentication-type md5
Spine-1(config-if)# fabricpath isis authentication key-chain Spine-1
Spine-1(config-if)# show fabricpath isis interface e2/4
Fabricpath IS-IS domain: default
Interface: Ethernet2/4
Status: protocol-up/link-up/admin-up
Index: 0x0003, Local Circuit ID: 0x01, Circuit Type: L1
Authentication type MD5Authentication keychain is Spine-1Authentication check specifiedExtended Local Circuit ID: 0x1A083000, P2P Circuit ID: 0000.0000.0000.00
Retx interval: 5, Retx throttle interval: 66 ms
LSP interval: 33 ms, MTU: 1500
P2P Adjs: 0, AdjsUp: 0, Priority 64
Hello Interval: 10, Multi: 3, Next IIH: 00:00:05
Level   Adjs   AdjsUp  Metric   CSNP  Next CSNP  Last LSP ID
1          0        0     400     60  Inactive   ffff.ffff.ffff.ff-ff
Topologies enabled:
Level Topology Metric  MetricConfig Forwarding
0     0        400     no           UP
1     0        400     no           UP
Spine-1(config-if)# show fabricpath isis adjacency
Fabricpath IS-IS domain: default Fabricpath IS-IS adjacency database:
System ID       SNPA            Level  State  Hold Time  Interface
Leaf-1          N/A             1      UP     00:00:23   Ethernet2/1
Leaf-2          N/A             1      UP     00:00:32   Ethernet2/2
Spine-2         N/A             1      LOST   00:04:53   Ethernet2/4 ———-> Adjacency is lost
We will see that once we configure Spine-2 with same key, adjacency will be resumed.
Spine-2(config)# key chain Spine-1
Spine-2(config-keychain)# key 1
Spine-2(config-keychain-key)# key-string Spine-1
Spine-2(config-keychain-key)# int e2/4
Spine-2(config-if)# fabricpath isis authentication-type md5
Spine-2(config-if)# fabricpath isis authentication key-chain Spine-1
Spine-2(config-if)# show fabricpath isis adjacency
Fabricpath IS-IS domain: default Fabricpath IS-IS adjacency database:
System ID       SNPA            Level  State  Hold Time  Interface
Leaf-1          N/A             1      UP     00:00:29   Ethernet2/1
Leaf-2          N/A             1      UP     00:00:27   Ethernet2/2
Spine-1         N/A             1      UP     00:00:30   Ethernet2/4
2. Domain Authentication: This will prevent routes from being learned, however will not have any impact on adjacencies.
Spine-1(config)# fabricpath domain default
Spine-1(config-fabricpath-isis)# authentication-type md5
Spine-1(config-fabricpath-isis)# authentication key-chain Spine-1
Spine-1(config)# show fabricpath isis
Fabricpath IS-IS domain : default
System ID : 5001.0001.002f  IS-Type : L1 Fabric-Control SVI: Unknown
SAP : 432  Queue Handle : 15
Maximum LSP MTU: 1492
Graceful Restart enabled. State: Inactive
Last graceful restart status : none
Graceful Restart holding time:60
Metric-style : advertise(wide), accept(wide)
Start-Mode: Complete [Start-type configuration]
Area address(es) :
00
Process is up and running
CIB ID: 1
Interfaces supported by Fabricpath IS-IS :
Ethernet2/1
Ethernet2/2
Ethernet2/4
Level 1
Authentication type: MD5Authentication keychain: Spine-1  Authentication check specifiedLSP Lifetime: 1200
L1 LSP GEN interval- Max:8000 Initial:50      Second:50
L1 SPF Interval- Max:8000     Initial:50      Second:50
MT-0 Ref-Bw: 400000
Max-Path: 16
Address family Swid unicast :
Number of interface : 3
Distance : 115
L1 Next SPF: Inactive
We can see that though adjacency is still there, System ID is not resolving the host Name and also routes are lost.
Spine-1# show fabricpath isis adjacency
Fabricpath IS-IS domain: default Fabricpath IS-IS adjacency database:
System ID       SNPA            Level  State  Hold Time  Interface
5001.0003.002f  N/A             1      UP     00:00:22   Ethernet2/1
5001.0004.002f  N/A             1      UP     00:00:29   Ethernet2/2
5001.0002.002f  N/A             1      UP     00:00:25   Ethernet2/4
Spine-1# show fabricpath route
FabricPath Unicast Route Table
‘a/b/c’ denotes ftag/switch-id/subswitch-id
‘[x/y]’ denotes [admin distance/metric]
ftag 0 is local ftag
subswitch-id 0 is default subswitch-id
FabricPath Unicast Route Table for Topology-Default
0/1/0, number of next-hops: 0
via —- , [60/0], 0 day/s 05:23:24, local
Spine-1#
Once authentication is removed, routes are learned.
Spine-1(config-fabricpath-isis)# no authentication-type
Spine-1(config-fabricpath-isis)# no authentication key-chain
Spine-1(config-fabricpath-isis)# show fabricpath isis adjacency
Fabricpath IS-IS domain: default Fabricpath IS-IS adjacency database:
System ID       SNPA            Level  State  Hold Time  Interface
Leaf-1          N/A             1      UP     00:00:23   Ethernet2/1
Leaf-2          N/A             1      UP     00:00:26   Ethernet2/2
Spine-2         N/A             1      UP     00:00:22   Ethernet2/4
Spine-1(config-fabricpath-isis)# show fabricpath route
0/1/0, number of next-hops: 0
via —- , [60/0], 0 day/s 05:24:20, local
1/2/0, number of next-hops: 1
via Eth2/4, [115/400], 0 day/s 00:00:12, isis_fabricpath-default
1/3/0, number of next-hops: 1
via Eth2/1, [115/400], 0 day/s 00:00:12, isis_fabricpath-default
1/4/0, number of next-hops: 1
via Eth2/2, [115/400], 0 day/s 00:00:12, isis_fabricpath-default
Fabricpath Unicast Static Routes and Multiple ISIS topologies:
– We can configure unicast static routes to override the routes computed by dynamic protocols such as IS-IS in FabricPath.
Leaf-2# sh fabricpath route switchid 3
1/3/0, number of next-hops: 2
via Eth2/1, [115/800], 0 day/s 01:11:26, isis_fabricpath-default
via Eth2/2, [115/800], 0 day/s 01:44:19, isis_fabricpath-default
Leaf-2(config)# fabricpath route switch-id 3 ethernet 2/1
Leaf-2(config)# show fabricpath route switchid 3
1/3/0, number of next-hops: 1
via Eth2/1, [40/40], 0 day/s 00:00:06, static route
– By default MT0 is the topology being used by all Vlans. We can configure multiple topologies to map specific VLANs and specific features to that specific topology.
Leaf-2(config)# fabricpath topology 1
Leaf-2(config-fp-topology)# member vlan 10
Leaf-2(config-fp-topology)# exit
Leaf-2(config)# int e2/1
Leaf-2(config-if)# fabricpath topology-member 1
Leaf-2(config-if-fp-topology)# exit
Leaf-2(config-if)# show fabricpath topology vlan
Topo-Description                 Topo-ID   Configured VLAN List
——————————– ——— ————————————-
0                                0         1-9,11-4096
1                                1         10
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Saturday, 15 December 2018




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Saturday, 1 December 2018

Favourite Questions Asked in HR Interviews || NetworKHelp

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Favourite Questions Asked in HR Interviews || NetworKHelp

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Favourite Questions Asked in HR Interviews || NetworKHelp

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Access Control Lists - Cisco || Standard & Extended Access-list || Net...

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Wednesday, 28 November 2018

What is DHCP and How IP Helper Address Works? || LAB Practical || Networ...

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Top 10 Reasons to Get a Cisco Certification Now || NetworKHelp

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Top 10 Reasons to Get a Cisco Certification Now || NetworKHelp

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Top 10 Reasons to Get a Cisco Certification Now || NetworKHelp

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Tuesday, 27 November 2018

IT Multi Skill Walk in Interviews on 1st Dec 2018 || NetworKHelp

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Thursday, 22 November 2018

DMVPN | Hub And Spoke Design Considerations | NetworkHelp.Org

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Tuesday, 20 November 2018

DHCP (Dynamic Host Control Protocol) || NetworKHelp.Org

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Monday, 19 November 2018

Cisco Catalyst 3850 Series Switches - Cisco || NetworKHelp

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Saturday, 17 November 2018

OSPF Neighbor States – OSPF Neighbor Forming Process ||| NetworKHelp

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Thursday, 15 November 2018

EIGRP (Enhanced Interior Gateway Routing Protocol Day -2 || NetworKHelp

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Tuesday, 13 November 2018

EIGRP (Enhanced Interior Gateway Routing Protocol) ||| NetworKHelp

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Monday, 12 November 2018

International Tech Park Gurugram !!! NetworKHelp

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Tuesday, 6 November 2018

Submarine Network !! Cable Map 2018 !!! NetworKHelp.Org

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Tuesday, 18 September 2018

                                         Professional/Technical Competencies:







 OSI & TCP/IP Network protocol architecture, Layering benefits and concept, functions of different layers, switches and LAN design, VLAN’s, VTP, STP, RSTP, MSTP. 
 Cisco Router & Switch experience with emphasis on IOS / CatOS, NxOS.
 Excellent knowledge in Nexus Technologies (OTV, VPC, FABRICPATH)  & Hardware (7K, 5K, 2K etc).
 First hop redundancy protocols (i.e. HSRP, VRRP, GLBP etc)
 Experience on configuration and maintenance of F5/ ACE load balancer.
 Proficient knowledge in Routing protocols (RIP, BGP, OSPF, EIGRP, IPX etc) especially in OSPF & BGP.
 WAN transport technologies (Frame Relay, ATM, Private/Leased Line, MPLS, ISDN, PPP, HDLC)
 Proficient knowledge in LAN technologies (Ethernet, Fast Ethernet, Gigabit Ethernet, Wi-Fi)
 VPN Technologies (IPSec, SSL, Cisco Anyconnect, Cisco EasyVPN, DMVPN) 
 Experience on troubleshooting various Site to site and Remote access VPN related issues.
 Authentication, authorization, encryption mechanisms (LDAP, RADIUS, TACACS+, PKI, SSL, SSH)                                               
 Quality of Service, Multicasting
 Excellent Knowledge on F5/ACE load balancer.
 Wireless LAN technologies, Cisco unified wireless LAN solution etc.                                                                                                      
 Excellent understanding of the protocols like FTP, TFTP, HTTP, DHCP, DNS, SNMP, WINS, IPSEC.  
 WAN Acceleration & compression services
Experience on configuration and maintenance of Cisco multilayer switches, Cisco routers.

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Thursday, 13 September 2018


      Multiple Spanning Tree Protocol (802.1s)
Now that we have basic understanding of how MSTP works inside a region let’s create a sample configuration. Consider the following physical topology of three switches:

The topology has the following VLANs: 1, 10, 20, 30, 40, 50, 60. Our goals for this scenario are:
  • Make VLANs 10,20,30 follow the link from SW3 to SW1.
  • Make VLANs 40,50,60 follow the link from SW3 to SW2.
  • If any of the above links fail, the affectred VLANs should fall-back to the other link.
To accomplish this, we create two MSTIs – number 1 and 2. SW1 will be the root for instance 1 and SW2 will be the root for instance 2. As for the IST (MSTI0), we make SW3 the root switch for it (though it’s not recommended to assign root roles to access switches). As for VLAN to MSTI mappings, VLAN 1 will remain mapped to the IST. Remaining VLANs 10, 20 and 30 would map MSTI1, while VLANs 40, 50 and 60 would map to MSTI2. Here is the configuration:


W1:
spanning-tree mode mst
!
spanning-tree mst configuration
 name REGION1
 instance 1 vlan 10, 20, 30
 instance 2 vlan 40, 50, 60
!
! Root for MSTI1
!
spanning-tree mst 1 priority 8192
!
interface FastEthernet0/13
 switchport trunk encapsulation dot1q
 switchport mode trunk
!
interface FastEthernet0/16
 switchport trunk encapsulation dot1q
 switchport mode trunk

SW2:
spanning-tree mode mst
!
spanning-tree mst configuration
 name REGION1
 instance 1 vlan 10, 20, 30
 instance 2 vlan 40, 50, 60
!
! Root for MSTI 2
!
spanning-tree mst 2 priority 8192
!
interface FastEthernet0/13
 switchport trunk encapsulation dot1q
 switchport mode trunk
!
interface FastEthernet0/16
 switchport trunk encapsulation dot1q
 switchport mode trunk

SW3:
spanning-tree mode mst
!
spanning-tree mst configuration
 name REGION1
 instance 1 vlan 10, 20, 30
 instance 2 vlan 40, 50, 60
!
! Root for the IST
!
spanning-tree mst 0 priority 8192
!
interface FastEthernet0/13
 switchport trunk encapsulation dot1q
 switchport mode trunk
!
interface FastEthernet0/16
 switchport trunk encapsulation dot1q
 switchport mode trunk

The following show commands will demonstrate the effect our configuration has on traffic forwarding:

SW1#show spanning-tree mst configuration
Name      [REGION1]
Revision  0     Instances configured 3

Instance  Vlans mapped
--------  ---------------------------------------------------------------------
0         1-9,11-19,21-29,31-39,41-49,51-59,61-4094
1 10,20,30
2 40,50,60
-------------------------------------------------------------------------------

SW1#show spanning-tree mst               

##### MST0    vlans mapped:   1-9,11-19,21-29,31-39,41-49,51-59,61-4094
Bridge        address 0019.5684.3700  priority      32768 (32768 sysid 0)
Root          address 0012.d939.3700  priority      8192  (8192 sysid 0)
              port    Fa0/16          path cost     0
Regional Root address 0012.d939.3700  priority      8192  (8192 sysid 0)
                                      internal cost 200000    rem hops 19
Operational   hello time 2 , forward delay 15, max age 20, txholdcount 6
Configured    hello time 2 , forward delay 15, max age 20, max hops    20

Interface        Role Sts Cost      Prio.Nbr Type
---------------- ---- --- --------- -------- --------------------------------
Fa0/13 Desg FWD 200000    128.15   P2p
Fa0/16 Root FWD 200000    128.18   P2p 

##### MST1 vlans mapped: 10,20,30
Bridge        address 0019.5684.3700  priority      8193  (8192 sysid 1)
Root this switch for MST1

Interface        Role Sts Cost      Prio.Nbr Type
---------------- ---- --- --------- -------- --------------------------------
Fa0/13 Desg FWD 200000    128.15   P2p
Fa0/16 Desg FWD 200000    128.18   P2p 

##### MST2 vlans mapped: 40,50,60
Bridge        address 0019.5684.3700  priority      32770 (32768 sysid 2)
Root address 001e.bdaa.ba80 priority 8194  (8192 sysid 2)
              port    Fa0/13          cost          200000    rem hops 19

Interface        Role Sts Cost      Prio.Nbr Type
---------------- ---- --- --------- -------- --------------------------------
Fa0/13 Root FWD 200000    128.15   P2p
Fa0/16           Altn BLK 200000    128.18   P2p 

SW1#show spanning-tree mst interface fastEthernet 0/13

FastEthernet0/13 of MST0 is designated forwarding
Edge port: no             (default)        port guard : none        (default)
Link type: point-to-point (auto)           bpdu filter: disable     (default)
Boundary : internal                        bpdu guard : disable     (default)
Bpdus sent 561, received 544

Instance Role Sts Cost      Prio.Nbr Vlans mapped
-------- ---- --- --------- -------- -------------------------------
0 Desg FWD 200000    128.15   1-9,11-19,21-29,31-39,41-49,51-59
                                     61-4094
1 Desg FWD 200000    128.15   10,20,30
2 Root FWD 200000    128.15   40,50,60

SW1#show spanning-tree mst interface fastEthernet 0/16

FastEthernet0/16 of MST0 is root forwarding
Edge port: no             (default)        port guard : none        (default)
Link type: point-to-point (auto)           bpdu filter: disable     (default)
Boundary : internal                        bpdu guard : disable     (default)
Bpdus sent 550, received 1099

Instance Role Sts Cost      Prio.Nbr Vlans mapped
-------- ---- --- --------- -------- -------------------------------
0        Root FWD 200000    128.18   1-9,11-19,21-29,31-39,41-49,51-59
                                     61-4094
1 Desg FWD 200000    128.18   10,20,30
2 Altn BLK 200000    128.18   40,50,60

The link cost values are much higher than the default STP costs (IEEE standard values), and MSTIx is called MSTx (e.g. IST is MST0). Aside from that, note the term “Regional Root” which is to be explained in details below.

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Related Topics
• What is Broadcast Storm
• What is Layer 2 Switching loop
• What is Spanning Tree Protocol (STP)
• What is Bridge Protocol Data Unit (BPDU) frame
• Bridge Protocol Data Unit (BPDU) Frame Format
• What is a Root Bridge (Switch)
• What is a Root Port
• What are Port Cost, Port Priority and Path Cost Values
• How Spanning Tree Protocol (STP) select Root Port
• What is a Designated Port
• How Spanning Tree Protocol (STP) select Designated Port
• Difference between Root Port and Designated Port
• Spanning Tree Port States
• Topology Changes in Spanning Tree Protocol (STP)
• Spanning Tree Protocol (STP) Convergence
• What is Spanning Tree Protocol (STP) PortFast
• How to configure and verify Spanning Tree Protocol (STP) PortFast
• How to enable or disable Spanning Tree Protocol (STP)
• What is Rapid Spanning Tree Protocol (RSTP)
• Difference between Spanning Tree Protocol (STP) and Rapid Spanning Tree Protocol (RSTP)
• Per-VLAN Spanning Tree (PVST) and Per-VLAN Spanning Tree Plus (PVST+)
• What are Spanning Tree Bridge Priority and Bridge ID values
• Spanning Tree Path Cost Value and How is Spanning Tree Path Cost Value Calculated
• Spanning Tree Port Priority and Port ID Values
• How to change Spanning Tree Bridge Root Priority value and What is Extended System ID
• How to configure Spanning Tree Protocol Root Primary and Root Secondary
• What is a Root Bridge (Root Switch)
• How to change Spanning Tree Port Priority Value
• How Spanning Tree Protocol (STP) select Root Port
• What is a Designated Port
• How Spanning Tree Protocol (STP) select Designated Port
• Difference between Root Port and Designated Port
• Spanning Tree Port States
• How BPDU is generated and How BPDU works
• Important Spanning Tree Protocol (STP) Timers and their default values
• How to Configure and Change Spanning Tree Protocol (STP) Default Timer-Values for hello timer, forward delay timer and max age timer
• Topology Changes in Spanning Tree Protocol (STP)
• Spanning Tree Protocol (STP) Convergence
• Where to place the Spanning Tree Protocol Root Switch (Root Bridge)
• Spanning Tree Protocol (STP) UplinkFast, Backbone Fast and Portfast
• What is Spanning Tree Protocol (STP) Uplink Fast
• What is Spanning Tree Protocol (STP) Backbone Fast
• What is Spanning Tree Protocol (STP) PortFast
• How to configure and verify Spanning Tree Protocol (STP) PortFast
• How to enable or disable Spanning Tree Protocol (STP)
• What is Rapid Spanning Tree Protocol (RSTP)
• Difference between Spanning Tree Protocol (STP) and Rapid Spanning Tree Protocol (RSTP)
• Per-VLAN Spanning Tree (PVST) and Per-VLAN Spanning Tree Plus (PVST+)
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Wednesday, 12 September 2018


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