ajout Etherchannel

00. Jeremy's IT LAB CCNA course.md

@@ -29,3 +29,10 @@ tags:
 [[VLAN (Part 2)]]
 [[VLAN (Part 3)]]
 [[DTP - VTP]]
+[[Protocole Spanning Tree (part1)]]
+[[Protocole Spanning Tree (part2)]]
+[[PortFast (STP Toolkit)]]
+[[BPDU Guard & BPDU Filter (STP Toolkit)]]
+[[Root Guard (STP Toolkit)]]
+[[Rapid Spanning Tree Protocol]]
+[[EtherChannel]]

20. Protocole Spanning Tree (part1).md

@@ -0,0 +1,140 @@
+---
+id: 20. Protocole Spanning Tree
+aliases: []
+tags: []
+---
+
+# Protocole Spanning Tree
+
+## Networks Redundancy
+
+- Redundandy is an essential part of network design.
+- Modern networks are expected to run 24/7/365
+- if one network component fails, you must ensure that other components will take over
+with little or no downtime
+- As much as possible, you must implement redundancy at every possible point in the network
+
+      note: Most PCs only have a single network interface card [[NIC]], so they can only be plugged
+      into a single switch. However, important servers typically have multiple NICs, so they can be
+      plugged into multiple switches for redundancy
+
+The [[Ethernet header]] doesn't have a [[TTL]] field. These broadcast frames will loop around
+the network indefinitely, if enough of these looped broadcasts accumulate in the network, the 
+network will be too congested for legitimate traffic to use the network. This is called 
+[[Broadcast Storm]]
+
+Network congestion isn't the only problem. each time a frame arrives on a switchport, the switch
+uses the source [[MAC]] address field to learn the MAC address and update its MAC address table.
+When a frames with the same source MAC address repeatedly arrive on different interfaces,
+the switch is continously updating the interface in its MAC address table. this is known as 
+[[MAC Address Flapping]]
+
+## Spanning Tree protocol
+
+- Classic Spanning Tree Protocol is **IEEE 802.1D**
+- Switches from all vendors run STP by default.
+- STP prevents Layer 2 loops by placing redundant ports in a blocking state, essentially disabling
+the interface.
+- These interfaces act as backups that can enter a forwarding state if an active (=currently forwarding)
+interface fails
+- Interfaces in a frowarding state behave normally. They send and receive all normal traffic.
+- Interfaces in a blocking state only send or receive STP messages (called **[[BPDU]]s**)
+Bridge Protocol Data Units
+
+      note: Spanning Tree Protocol still use the term [[Bridge]]. However, when we use the term 
+      bridge, we really mean [[Switch]]. Bridges are not used in modern networks.
+
+- By selecting which ports are forwarding and which ports are blocking, STP creates a single path to/from
+each point in the network. This prevents Layer 2 loops.
+- There us a set process that STP uses to determine which ports should be forwartding and which should 
+be blocking
+- STP-enanbled switches send/receive Hello BPDUs out of all interfaces, the default timer is 
+2 seconds (the switch will send a Hello BPDU out of every interface, once every 2 secong)
+- If a switch receives a Hello BPDUs on an interface, it knows that interface is connected to another 
+switch (routers, PCs, etc. do not use STP, so they do not send Hello BPDUs)
+
+- Switches use one field in the STP BPDU, the Bridge ID field, to elect a root bridge for the network
+- The switch with the lowest Bridge ID becomes the root bridge.
+- ALL ports on the root bridge are put in a forwarding state,and other switches in the topology
+must have a path to reach the root bridge
+
++---------------------------------+
+|            Bridge ID            |
+|------------------+--------------|
+| Bridge Priority  |  Mac address |
+|     16 bits      |  48 bits     |
++---------------------------------+
+
+The default bridge priority is 32768 on all switches, so by default the MAC address is used 
+as the tie-breaker (lowest MAC address becomes the root bridge)
+
+**The Bridge Priority is compared first. if they tie, the MAC address is then compared**
+
+Howerver the Bride ID have been updated
+
++---------------------------------+
+|            Bridge ID            |
+|------------------+--------------|
+| Bridge Priority  |  Mac address |
+|     16 bits      |  48 bits     |
++---------------------------------+
+         |
++----------------------------+
+| Bridge | Extended System ID|
+|Priority|    (VLAN ID)      |
+|  4bits |     12 bits       |
++----------------------------+
+
+Cisco switches use a version of STP called PVST (per-VLAN Spanning Tree).
+PVST runs a separate STP instance in each VLAN, so in each VLAN different interfaces
+can be forwarding/blocking
+
+in the default VLAN of 1, the default bridge priority is actually 32769 (32768 + 1)
+
+The STP bridge priority can only be changed in units of 4096
+
+All interface on the root bridge are **designated ports**. designated ports are in a forwarding state
+
+Whe a switch is powered on, it assumes it is the root bridge.
+it will only give up its position if it receives a superior BPDU (lower bridge ID)
+
+Once the topology has converged and all switches agree on the root bridge, only the root bridge sends BPDUs
+Other switches in the network will forward these BPDUs, but will not generate their own original BPDUs
+
+### STP Cost
+
+| Speed | STP Cost |
+| -------------- | --------------- |
+| 10Mbps | 100 |
+| 100Mbps | 19 |
+| 100Gbps | 4 |
+| 10Gbps | 2 |
+
+The ports connected to another switch's root port MUST be designated. Because the root port is the switch's path to the root bridge
+another switch must not block it
+
+### Port ID
+
+STP Port ID = port priority (default 128) + port number
+
+Every collision domain has a single STP designated port
+
+### Steps
+
+1) The switch with the lowest bridge ID is elected as the root bridge. All ports on the root bridge are designated ports (forwarding state).
+2) Each remaining switch will select ONE of its interfaces to be its root port. The interface with the lowest root cost will
+be the root port. Root ports are also in a forwarding state
+Root port selection:
+  - lowest root cost
+  - lowest neighbor bridge ID
+  - lowest neighbor port ID
+3) Each remaining collision domain will select ONE interface to be a designated port (forwarding state). THe other port in the
+collision domain will be non-designated (blocking)
+Designated port selection:
+  - Interface on switch wih lowest root cost
+  - Interface on switch wih lowest bridge ID
+  
+## Review
+
+- Redundancy in networks
+- STP (Spanning Tree Protocol)

21. BPDU Guard & BPDU Filter (STP Toolkit).md

@@ -0,0 +1,167 @@
+---
+id: 1779916771-SNCX
+aliases:
+  - BPDU Guard & BPDU Filter (STP Toolkit)
+tags: []
+---
+
+# BPDU Guard & BPDU Filter (STP Toolkit)
+
+PortFast makes a port start in the Forwarding state when it is connected, but it doesn't disable STP
+on the port.
+- The port will continue to send BPDUs every 2 seconds.
+
+Because end hosts don't run STP and send BPDUs, a PortFast enabled port shouldn't receive BPDUs
+- But what if it does?
+
+If a PortFast-enabled port receives an STP BPDU, it will revert to acting like a regular STP port
+(without PortFast)
+
+## BPDU Guard
+
+### The problem
+
+PortFast should only be enabled on ports connected to non-switch devices (end osts, routers).
+- A PortFast-enabled port still sends BPDUs and will operate like a regular STP port if it 
+receives VPDUs from a neighbor.
+- If an end user carelessly connects a switch to a port meant for end hosts,, it could affect the
+STP topology.
+- *BPDU Guard* acts as a safeguard against this.
+
+### The Solution
+
+BPDU Guard protects the network from unauthorized switches being connected to ports intended for end hosts.
+It can be configured separately from [[PortFast]] but both features are usually used together.
+They both enhance STP's functionality on ports inteded for end hosts.
+
+A BPDU Guard-enabled port contibues to send BPDUs, but if it receives a BPDU it enters the error-disabled state.
+- In effect, this disbales the port.
+
+### Configuration
+
+Like PorFast, BPDU Guard can be configured in two ways:
+
+per-port:
+```Cisco
+SW3(config-if)# spanning-tree bpduguard enable
+```
+
+default
+```Cisco
+SW3(config)# spanning-tree portfast bpduguard default
+```
+
+When enabled by default *BPDU Guard* is activated on **All Portfast-enabled ports**.
+
+disableing it
+```Cisco
+SW3(config)# spanning-tree bpduguard disable
+```
+
+### Errdisable
+
+ErrDiable is a [[Cisco]] switch feature that disables a port under certain conditions, such as BPDU 
+Guard violation.
+More examples are
+- Power Policing violations
+- Port Security violations
+- DAI (Dynamic ARP inspection) violations
+
+to re-enable an err-disabled port, *first solve the underlying issue*
+- if you re0enable the port without fixing the issue, it will just be err-disabled again.
+
+You can re-enable an err-disabled  port in two ways:
+1. Manual: use *shutdown* and *no shutdown* to reset the disabled port.
+2. Automatic: *ErrDisable Recovery*
+
+#### ErrDisable Recovery
+
+ErrDisable Recovery is a feature that automatically re-enables err disabled ports after a certain period of time
+
+ErrDisable Recovery is disabled by default
+
+to view it status use
+
+```Cisco
+SW1# show errdisable recovery
+```
+
+The default recovery timer is 300 seconds (5minutes).
+- err-disabled interfaces will be automatically re-enabled after 5 minutes
+
+command to modify the interval is
+```Cisco
+SW1# errdisable recovery interval *seconds*
+```
+
+to enable ErrDisable Recovery for ports disabled by a particular cause use
+```Cisco
+SW1(config)# errdisble recovery cause *cause*
+```
+
+## BPDU Filter
+
+### The Problem
+
+A switch port connected to an end host contnues sending BPDUs every 2 seconds.
+- regardless of whether PortFast and/or BPDU GUard are enabled
+If the port doeen't connect to a switch, sending BPDUs is unnecessary and undesirable for a
+coupe of reasons
+1. Sendig BPDUs uses some bandwidth and processing power on the witch (althrough it's minimal).
+2. BPDUs contain information about the LAN's STP topology
+  - If maximum security is a concern, you should avoid sending this info to user devices.
+
+Bpdu Filter solves this by preventing a port from sending BPDUs
+
+### The Solution
+
+BPDU FIlter stops a port fro sending BPDUs
+- Unlike BPDU Guard, it does not disable the port if it receives a BPDU
+BPDU filter can be enabled in two ways:
+
+per-port:
+```Cisco
+SW3(config-if)# spanning-tree bpdufilter enable
+```
+The port will not send BPDUs
+The port will ignore any BPDUs it receives.
+In effect this disables [[STP]] on the port. *Use with caution!*
+
+default
+```Cisco
+SW3(config)# spanning-tree portfast bpdufilter default
+```
+BPDU Filter will be activated on all *PortFast-enabled ports*.
+  You can use spanning-tree bpdufilter disable to disable it on specific ports.
+The port will not send BPDUs
+If the port receives a BPDU, PortFast and BPDU Filter are disabled, and it operates as a normal STP Port.
+
+## Recommandation
+
+Enable PortFast and BPDU Guard however you prefer (per-port or by default)
+- Only enable BPDU Filter by default (global config mode).
+- Unless you have a very good reason to enable it per-port
+
+*BPDU Guard* and *BPDU Filter* can be enabled on the same port at the same time:
+
+---
+
+If BPDU Filter is enabled in global-confg mode and the port receives a BPDU:
+1. BPDU Filter will be disabled
+2. BPDU Guard will be triggered (and err-disable the interface)
+
+---
+
+If BPDU Fileter is enabled in interface config mode and the port receives a BPDU:
+- The BPDU will be ignored
+- BPDU Guard will *not* be triggered
+
+## Review
+
+### BPDU Guard 
+Automatically disables a port if it receives a BPDU, protecting the STP topology by preventing
+unauthorized devices from becoming part of the network
+
+
+### BPDU Filter
+Stops a port from sending BPDUs or processing received BPDUs

21. PortFast (STP Toolkit).md

@@ -0,0 +1,126 @@
+---
+id: 1779884291-BCDN
+aliases:
+  - PortFast (STP Toolkit)
+tags: []
+---
+
+# PortFast (STP Toolkit)
+
+ex:
+Switch <-> PC
+
+Listening
+   | 15sec
+Learning
+   | 15sec
+Forwarding
+
+When an end host connects to a switch port, the port becomes up/up but can't send/receive data yet.
+- It is a *Designated port* but will take 30 seconds before it enters the Forwarding state:
+  - 15 seconds in Listening
+  - 15 seconds in Learning
+This lead to poor user experience
+- the user probably doesn't even know [[STP]] exists.
+- They just know "the internet doesn't work" for 30 seconds when they connect their computer.
+- This wait is unnecessary, because there is no risk of a Layer 2 loop occuring between a switch/PC
+
+## The solution
+
+When portFast is configured on a port, the port immediately enters the Forwardin state when connected 
+to another device.
+It bypasses Listening/Learning and can send/receive data right away
+
+You can configure PortFast in two ways
+
+1. Interface config mode
+
+```Cisco
+SW1(config-if)# spanning-tree portfast
+```
+
+This enables PortFast only on the individual interface.
+
+*Even if you configure spanning-tree porfast on a trunk port, it won't be active.*
+
+2. Global config mode:
+
+```Cisco
+SW1(config)# spanning-tree portfast default
+```
+
+This enables PorFast on all access ports.
+
+      Connections between switches are almost always trunk links.
+      Connections to end hosts are almost always access links.
+
+**PortFast should NOT be configured on ports connected to switches or temporary Layer 2
+loops can occur.**
+
+## showing result
+
+```Cisco
+SW1(config)# show spanning-tree interface g0/1 detail
+```
+
+## diabling portfast
+
+```Cisco
+SW1(config-if)# spanning-tree portfast disable
+```
+
+## Configurating Portfast on trunk port
+
+In some cases, you might want to enable PortFast on a trunk port:
+- A port connected to a virtualization server with virtual machines (VMs) in different VLANs.
+- A port connected to a [[router]] via router on a stick [[ROAS]].
+
+This can only be cofigured per-port in interface config mode:
+
+```Cisco
+SW1(config-if)# spanning tree portfast trunk
+```
+
+## PortFast Edge
+
+In modern Cisco switches, if you use the commands covered in this lecture, the device will automatically
+add the edge keyword to the configuration.
+
+```Cisco
+SW1(config-if)# spanning-tree portfast
+running-config
+spanning-tree portfast edge
+```
+
+```Cisco
+SW1(config-if)# spanning tree portfast trunk
+running-config
+spanning-tree portfast edge trunk
+```
+
+```Cisco
+SW1(config)# spanning-tree portfast default
+running-config
+spanning-tree portfast edge default
+```
+
+You can use either version of the commands when configuring PortFast.
+
+The end result is the same: edge will always be added in the configuraion.
+
+spanning-tree portfast disable doesn't use the *edge* keyword.
+
+
+## two kind of Portfast
+
+There are two kinds of PortFast:
+-  edge
+  - edge is the kind we are covering in this video
+-  network
+  - network is used for a feature called Bridge Assurance (not a CCNA topic)
+
+## Review
+
+### PortFast:
+Allows switchs ports connected to end hosts to immediately enter the STP Forwarding state.
+Bypassing Linstening and Learning

21. Protocole Spanning Tree (part2).md

@@ -0,0 +1,226 @@
+---
+id: 1778913634-WEMK
+aliases:
+  - Protocole Spanning Tree (part2)
+tags: []
+---
+
+# Protocole Spanning Tree (part2)
+
+## Spanning Tree Port State
+
+| STP Port State | Stable/Transitional |
+| -------------- | --------------- |
+| Blocking | Statble |
+| Listening | Transitional |
+| Learning | Transitional |
+| Forwarding | Stable |
+| Disabled |  Stable |
+
+- Root/Designated ports remain stab;e in Forwarding state.
+- Non-designated ports remain stabl in a Blocking state.
+- Listening and Learning are transitional states which are passed through when an interface is 
+activated, or when a *Blocking* port must transition to a Forwarding state due to a change in the
+network topology
+
+### Blocking state
+
+- Non designated ports are in a Blocking state
+- Interfaces in a Blocking state are effectively disabed to prevent loops.
+- Interfaces in a Blocking stae do not send/receive regular naetwork traffic.
+- Interfaces in a Blocking state receive STP BPDUs.
+- Interfaces in a Blocing state do NOT forward STP BPDUs.
+- Interfaces in a Blocking state do NOT learn [[MAC]] addresses.
+
+### Listening state
+
+- After the Blocking state interfaces with the Designated or Root role enter Listening state.
+- Only Designated or Root ports enter the Listening state (Non-designated ports are always Blocking)
+- The Listening state is 15 seconds long by default. This is determined by the *orward delay* timer.
+- An interface in the listening state ONLY forwards/receives STP BPDUs.
+- An interface in the Listening state does NOT send/receive regular traffic
+- An interface in the Listening state does NOT Learn MAC addresses from regular traffic that
+arrives on the interface
+
+### Learning state
+
+- After the Listeing state, a Designated or ROOT port will enter Learning state.
+- The Learning state is 15 seconds long by default. This is determined by the Forward delay
+timer ( the same timer is used for both the Listening and Learning states).
+- An interface in the Learning state ONLY sends/receives STP BPDUs.
+- An interface in the Learning state learns MAC addresses from regular traffic that arrives on
+the interface.
+
+### Forwarding state
+
+- Root and designated ports are in a Forwarding state.
+- A port in the Forwarding state operate as normal
+- A port in the Forwarding state sends/receives BPDUs.
+- A port in the Forwarding state sends/receives normal traffic.
+- A port in the Forwarding state learns MAC addresses.
+
+### summary
+
+
+| STP Port State |Send/Receive BPDUs | Frame forwarding | Mac address learning| Stable/Transitional |
+| -------------- |----|----|----| --------------- |
+| Blocking | No/Yes|   NO | NO  | Statble |
+| Listening | Yes/Yes|   NO | NO  | Transitional |
+| Learning | Yes/Yes|   NO | Yes  | Transitional |
+| Forwarding | Yes/Yes|   Yes | Yes  | Stable |
+| Disabled | NO/NO|   NO | NO  | Stable |
+
+
+    note: Switches do not forward the BPDUs out of their root ports and non-designated ports,
+    only their designated ports
+
+## STP timers
+
+### Hello
+
+How often the root bridge sends hello BPDUs
+duration: 2 sec
+
+### Forward delay
+
+How long the switch will stay in the Listening and Learning states (each stae is 15 seconds 
+= total 30 seconds)
+duration: 15sec
+
+### Max Age
+
+How long an interface will wait after ceasing to receive Hello BDPUs to change the STP topology
+duration: 20 sec (10*hello)
+
+- If another BPDU i received before the max age timer counts down to 0, the time will reset to 20 
+seconds and no changes will ocur.
+
+- If another BPDU is not received the max age timer counts down to 0 and the switch will
+reevaluate its STP choices, including root bridge, and local root, designated, and non-designated ports
+
+- if a non-designated port is selected to become a designated or root port, it will transition 
+from the blocking state to the listening state (15 seconds), learning state (15 seconds),
+and then finally the forwarding state. So it can take a total of 50 seconds for a blocking
+interface to transition to forwarding
+
+- These timers and transitional states are to make sure that loops aren't accidentally created
+by interface moving to forwarding state too soon.
+
+      note: A forwarding interface can move directly to a blocking state (there is no worry
+      about creating a loop by blocking an interface).
+      A blocking interface cannot move directly to forwarding state, it must go through the
+      listening and learning states.
+
+```Wireshark
+Dst: PVST+ (01:00:0c:cc:cc:cd)
+```
+
+PVST = Only ISL trunk enquapsulation
+PVST+ = Supports [[802.1Q]]
+
+Regular STP (not Cisco's PVST+)
+uses a destination MAC address of 0180.c200.0000
+
+The STP timers on the root bridge determine the STP timers for th entire network.
+
+## Spanning Tree Optional Features (STP Toolkit)
+
+### Portfast
+
+Portfast allows a port to move imediately to the Forwarding state, 
+bypassing *Listening* and *Learning*.
+
+If used, it must be enabled *only on ports connected to end hosts,*
+if enabled on a port connected to another switch it could cause a Layer 2 loop.
+
+```Cisco
+SW1(config)#interface g0/2
+SW1(config-if)#spanning-tree portfast
+```
+
+You can also enable portfast with the  command:
+
+```Cisco
+SW1(config)#spanning-tree portfast default
+```
+
+This enables portfast on all access ports (not trunk ports).
+
+### BPDU Guard
+
+if an interface with BPDU Guard enabled receives a BPDU from another switch,
+the interface will be shut down to prevent a loop from forming.
+
+```Cisco
+SW1(config)#interface g0/2
+SW1(config-if)#spanning-tree bpduguard enable
+```
+
+You can also enable portfast with the  command:
+
+```Cisco
+SW1(config)#spanning-tree portfast bpduguard default
+```
+
+### Root Guard
+
+If you enable root guard on an interface, even if it receives a superior BPDU (lower bridge ID)
+on that interface , the switch will not accept the new switch as the root bridge.
+the interface will be disabled.
+
+### Loop Guard
+
+If you enable loop guard on an interface, even if the interface stops receiving BPDUs, it`will not 
+start forwarding. The interface will be disabled.
+
+## Spanning Tree Configuration
+
+
+### Spanning Tree mode
+
+```Cisco
+SW1(config)#spanning-tree mode ?
+  mst   multiple spanning tree mode
+  pvst  Per-Vlan spanning tree mode
+  rapid-pvst Per-Vlan rapid spanning tree mode //default
+
+SW1(config)#spanning-tree mode pvst
+```
+
+### Primary Root Bridge
+
+```Cisco
+SW1(config)#spanning-tree vlan 1 root primary
+
+SW1(config)#do show spanning-tree
+```
+
+The *spanning-tree vlan (vlan-number) root primary* command sets the STP priority to 24576.
+if another switch already has a priority lower than 24576, it sets this switch's priority 
+to 4096 less than the other switch's priority.
+
+### Secondary Root Bridge
+
+```Cisco
+SW1(config)#spanning-tree vlan 1 root secondary
+
+SW1(config)#do show spanning-tree
+```
+
+The *spanning-tree vlan (vlan-number) root secondary* command sets the STP priority to 28672.
+
+### STP Port Setting
+
+```Cisco
+SW1(config)#spanning-tree vlan 1 cost 200
+SW1(config)#spanning-tree vlan 1 port-priority 32
+
+```
+
+## Review
+
+
+- STP state/timers
+- STP BPDU
+- STP optional features
+- STP configuration

21. Root Guard (STP Toolkit).md

@@ -0,0 +1,72 @@
+---
+id: 1779981231-AJMV
+aliases:
+  - Root Guard (STP Toolkit)
+tags: []
+---
+
+# Root Guard (STP Toolkit)
+
+STP prevents loops by electing a root bridge and ensuring that each other switch has only *one valid path* to reach it.
+
+YOu shouldn't randomly select the root bridge. Some things you should consider include:
+- Optimal traffic flow
+  - minimize latency
+  - minimize congestion
+- Stability and reliability
+
+## The Problem
+
+Within your own [[LAN]], you can easily control the root brdige by setting its priority to 0.
+- But there are cases where you might connect your LAN to other switches outside of your direct control:
+  - A service provider offering Metro Ethernet service to customers
+    - Often used to connect sites within a [[MAN]] 
+- Even if you set your root bridge's priority to 0, its role can be taken by another switch with a lower
+  [[MAC address]] .
+
+## The solution
+
+- *Root Guard* can be configured to protect your [[STP]] topology by preventing your switches from
+  accepting superior [[BPDU]]s from switches outside of your control.
+  - Superior BPDUs = a BPDU that is superior in the STP algorith (e.g Claiming a better root bridge ID).
+If you want to ensure that the root bridge rmains in your [[LAN]], you can configure Root Guard on the ports connected
+to switches outside of your control
+
+To enable root Guard on a port
+
+```Cisco
+SW1(config-if) spanning-tree guard root
+```
+
+There is no command to enable it by default from global config mode
+
+If a Root Guard-enabled port receives a BPDU, it will enter the *Broken* (Root inconsistent) state
+effectively disabling it
+- The port will not able to forward data frames and will discard any frames it receives.
+
+To re-enable a port disabled by Root Guard, you must solve the issue that disabled the port
+  - the disabled port must stop receiving superior BDPUs.
+  - tell the customer to increase the priority value of their switch.
+
+Once teh superior BPDUs received age out, the ports will automatically be re-enabled.
+  - A BPDU's Max Age is 20 seconds by default.
+
+To see the Root guard
+
+```Cisco
+SW1(config-if)# do show spanning-tree
+
+## if it's broken
+Gi0/1  Desg BKN*4       128.3   P2p  *ROOT_Inc
+
+BKN = Broken
+ROOT_Inc = Root inconsistent
+
+## if it's Work
+Gi0/1  Desg FWD 4       128.3   P2p  
+```
+
+## Review
+
+ Prevents a port from becoming a Root Port by disabling it if superior BPDUs are received,
+Thereby enforcing the current [[Root Bridge]]

22 Rapid Spanning Tree Protocol.md

@@ -0,0 +1,185 @@
+---
+id: 22 Rapid Spanning Tree Protocol
+aliases: []
+tags:
+  - CCNA
+---
+
+# Rapid Spanning Tree Protocol 
+
+## Spanning Tree Version
+
+### Industry standards (IEEE)
+
+Spanning Tree Protocol (802.1D) 
+- The original STP
+- ALl VLANs share one STP instance.
+- Therefore, cannot load balance.
+
+Rapid spanning Tree Protocol (802.1w)
+- Much faster at converging/adaptating to network changes than 802.1D
+- All VLANs share one STP instance.
+- Therefore, cannot load balance
+
+Multiple Spanning Tree Protocol (802.1s)
+- Uses modified RSTP mechanics.
+- Can group multiple VLANs into different instacnces (ie. VLANs 1-5 instance 1, VLANs 6-10 in instance
+2 ) to perform load balancing
+
+### CISCO Versions
+
+Per-VLAN Spanning Tree Plus (PVST+)
+- Cisco's upgrade to 802.1D
+- Each VLAN has its own STP instance.
+- Can load balance by blocking different ports in each VLAN.
+
+Rapid Per-VLAN Spanning Tree Plus (Rapid PVST+)
+- Cisco's upgrade to 802.1w
+- Each VLAN has its own STP instance
+- Can load balance by blocking different ports in each VLAN
+
+## Rapid spanning Tree Protocol
+
+Cisco's summary:
+"RSTP is not a timer-based spanning tree algorithm like 802.1D. therefore, RSTP offers an improvement 
+over the 30 seconds or more that 902.1d takes to move a link to forwarding. the heart of
+the protocol is new bridge-bridge handshake mechanism, which allows ports to move directly to forwarding."
+
+### Similarities between STP and RSTP:
+
+RSTP serves the same purpoe as STP, blocking specific ports to prevent Layer2 loops.
+- RSTP elect a root bridge with same rules as STP
+- RSTP elects root ports with the same rules as STP.
+- RSTP elects designated ports with the same rules as STP
+
+### Differences
+
+#### COST
+
+| speed | STP COST | STP COST |
+| -------------- | --------------- | --------------- |
+| 10 Mbps | 100 | 2,000,000 |
+| 100 Mbps | 19 | 200,000 |
+| 1 Gbps | 4 | 20,000 |
+| 10 Gbps | 2 | 2,000 |
+| 100 Gbps | x | 200 |
+| 1 Tbps | x | 20 |
+
+
+#### Port State
+
+| STP Port State | Send/Receive BPDUs | Frame Forwarding | MAC Learning | Stable/Transitional |
+| ------------- | -------------- |  -------------- | -------------- | -------------- |
+| Discarding | NO/YES | NO | NO | Stable | 
+| Learing | YES/YES | NO | YES | Tranisitional | 
+| Forwarding | YES/YES | YES | YES | Stable | 
+
+
+- if a port is administratively disabled (shutdown command) = discarding state
+- if a port is enabled but blocking traffic to prevent Layer 2 loops = discarding state
+
+#### Port Roles
+
+*The root port role remains unchanged in RSTP.*
+- The port wthat is closet to the root bridge becomes the root port for the switch.
+- The root bridge is the only switch that doesn't have a root port.
+
+*The designated port role remains unchanged in RSTP.*
+- The port on a segment (collision domain) that sends the best BPDU is that 
+segment's designated port (only one per segment)
+
+- *The non designated port role is split into two separate roles in RSTP*:
+  - The alternate port role 
+  - the backup port role
+
+##### Alternate port Role
+
+The RSTP alternate port role is discarding port that receives a superior BPDU from another switch.
+- This is the same as what you've learned about *blocking*  ports in classic STP.
+- Functions as a backup to the root port.
+- If the root port fails, the switch can immediately move its best alternate port to forwarding
+
+      This immediate move to fowarding state functions like a classic STP optional feature called 
+      UplinkFast. Because it is built into RSTP, you do not need to activate UplinkFast when using 
+      RSTP/Rapid PVST+
+
+      One more STP optional feature that was built into RSTP is BackboneFast.
+      Backbone Fast allows SW3 to expire the made age timers on its interface and rapidly forward the superior
+      BPDUs to SW2.
+      This functionality is built into RSTP, so it does not need to be configured
+
+##### Backup port role
+
+The RSTP backup port role is a discarding port that receives a superior BPDU from another 
+interface on the same switch.
+- This only happnes when two interfaces are connected to the same collision domain (via a hub)
+- Hubs are not used in modern networks, so you will probably not encounter an RSTP backup port.
+- Function as backup for a designated port
+- The interface with the lowest port ID will be selected as the designated port and the other will be the
+backup port
+
+### BPDU
+
+In classic [[STP]], only the root bridge originated BPDUs, and other switches just forwarded the BPDUs
+they received.
+In Rapid STP, all Switches originate and send their own BPDUs from their designated ports
+
+All switches running Rapid STP send their own BPDUs every hello time (2 seconds).
+- Switches 'age' the BPDU information much more quickly, in classic STP a switch waits 10 hello intervales
+(20 seconds). In rapid STP, a switch considers a neighbor lost if it misses 3 BPDUs (6 seconds)
+It will the 'Flush' All MAV addresses learned on that interface
+
+## RSTP Link Types
+
+RSTP distiguishes between three different 'link types'
+- Edge: a port that is connected to an end host. Moves directly to forwarding without negotiation.
+- Point-to-point: a direct connection between two switches
+- Shared a connection to a [[hub]]. Must operate in half-duplex mode.
+
+### Edge
+
+Edge ports are connected to end hosts.
+- Because ther is no risk of creating a loop, they can move stright to the forwarding state without the 
+negotiation process.
+- They function like a classic STP port with PortFast enabled
+
+```Cisco
+SW1(config-if)# spanning-tree portfast
+```
+
+### Point-to-Point
+
+Point-to-point ports connect directly to another switch
+- They function in full-duplex
+- you don't need to configure the interface as point-to-point (it should be detected)
+
+```Cisco
+SW1(config-if)# spanning-tree link-type point-to-point
+```
+
+
+### Shared
+
+shared Ports connect to another switch (or switches) via a hub.
+- They function in half-duplex
+- You don't need to configure the interface as shared (it should be detected)
+
+```Cisco
+SW1(config-if)# spanning-tree link-type shared
+```
+
+### Configuration
+
+
+```Cisco
+SW3(config)# spanning-tree mode rapid-pvst
+
+SW3(config)# do show spanning-tree
+```
+
+
+## Review
+
+Comparison of [[STP]] versions (standard vs [[Cisco]])
+
+Rapid PVST+

23. EtherChannel.md

@@ -0,0 +1,128 @@
+---
+id: 23. EtherChannel
+aliases: []
+tags: []
+---
+
+# EtherChannel
+
+multiple host -- ASW1 -- DSW1
+
+ASW = Access layer Switch, a switch that end hosts connect to
+DSW = Distribution layer switch, a switch that access layer switches connect to
+
+When the bandwith of the interfaces connected to end hosts is greater than the bandwidth of the 
+connection to the distribution switch(es), this is called *oversubscription*.
+Some oversubscription is acceptable, but too much will cause congestion.
+
+- if you connect two switchs together with multiple links, all except one will be disabled by 
+[[spanning tree]]
+- if all of ASW1's interfaces were forwarding, Layer 2 loops would form between ASW1 and DSW1, 
+leading to [[broadcast storms]].
+- Other links will be unused unless the active link fails. in that case one of the inactive
+links will start forwarding
+- EtherChannel groups multiple interfaces together to act as a single interface.
+- STP will treat this group as a single interface
+
+Traffic using the EtherChannel wil be load balanced among the physical interfaces in the group. 
+An [[algorithm]] is used to determine which traffic will use which physical interface.
+
+Some other names for an EtherChannel are:
+- Port Channel
+- LAG (Link aggregaton Group)
+
+## Load Balancing
+
+- EtherChannel load balances based on flows
+- A flow is a communication between two nodes in the network
+- Frames in the same flow will be forwarded using the same physicial interface.
+- If frames in the same flow were forwarded using different physical interfaces, some frames
+may arrive at the destination out of order, which can cause problems
+- You can change the inputs used in the interface selection calculation.
+- Inputs that can be used:
+  - Source [[MAC]]
+  - Destination MAC
+  - Source and Destination MAC
+  - Source [[IP]]
+  - Destination IP
+  - Source and Destination IP
+
+### Commands
+
+
+see current configuration
+```Cisco
+ASW1#show etherchannel load-balance
+### default will be set to src-dst-ip
+```
+
+for configuring load balance configuration
+```Cisco
+ASW1(config)#port-channel load-balance src-dst-mac
+
+## to see other method
+ASW1(config)#port-channel load-balance ?
+```
+
+## EtherChannel Configuration
+
+There are three methods of EtherChannel configuration on Cisco switches:
+- PAgP (Port Aggregation Protocol)
+  - Cisco proprietary protocol 
+  - Dynamically negotiates the creation/maintenance of the EtherChannel.
+  (like DTP does for trunks)
+- LACP (Link Aggregation Control Protocol)
+  - Industry standard protocol (IEEE 802.3ad)
+  - Dynamically negotiate the creation/maintenance of the EtherChannel.
+  (like DTP does for trunks)
+- Static EtherChannel
+  - A protocol isn't used to determine if an EtherChannel should be formed.
+  - Interfaces are statically configured to form an EtherChannel
+
+Up to *8 interfaces* can be formed into a single EtherChannel (LACP allows up to 16, but only
+8 will be active, the other 8 will be in standby mode, waiting for an active interface to fail)
+
+```Cisco
+ASW1(config)#inteface range g0/0 - 3
+## to see all methods
+ASW1(config-if-range)#channel-group 1 mode ?
+## for PAgP
+ASW1(config-if-range)#channel-group 1 mode desirable
+```
+
+    note: The channel-group number has to match for member interfaces on the same switch.
+    However, it doesn't have to match the channel-group number on the other switch.
+    (channel-group 1 on ASW1 can form an EhterChannel with channel-group 2 on DSW1)
+ 
+Member intefaces must have matching configurations.
+- Same duplex (full/half)
+- Same speed
+- Same switchport mode (access/trunk)
+- Same allowed VLANs/native VLAN (for trunk interfaces)
+
+If an interface's configurations do not match the others, it will be excluded from the EtherChannel
+
+to see running configuration of the EtherChannel
+
+```Cisco
+ASW1#show etherchannel summary
+## less utilise command
+ASW1#show etherchannel port-channel
+```
+
+## Layer 3 EtherChannel
+
+```Cisco
+ASW1(config)#int range g0/0 - 3
+ASW1(config-if-range)#no switchport
+ASW1(config-if-range)#channel-group 1 mode active
+
+
+ASW1(config-if-range)#int po1
+ASW1(config-if)#ip address 10.0.0.1 255.255.255.252
+```
+
+## Review
+
+- What is EtherChannel? what problems does it solve?
+- Configuring Layer 2/Layer 3 EtherChannel