The command interface vxlan vtep-stacking followed by map vni 10010 vlan 100 maps the VLAN traffic that an SVLAN identifies to a VNI on a VTEP. In this context, SVLAN (Service VLAN) is being mapped to a VXLAN Network Identifier (VNI) for encapsulation and transport across the VXLAN tunnel.
References:
* Dell Technologies SONiC documentation
* VXLAN Configuration Guide

An iBGP (Internal Border Gateway Protocol) neighbor relationship is established between two BGP routers within the same autonomous system (AS). This relationship allows for the exchange of routing information within the AS, ensuring that internal routes are propagated correctly.
References:
* Dell Technologies SONiC Routing Guide
* BGP Configuration Guide

see the explanation for all step by step solution with all explanation.
Explanation:
Here are the steps to configure the peer link on SwitchA:
* Enter Configuration Mode:
SwitchA# configure terminal
* Create VLAN 101:
SwitchA(config)# vlan 101
* Create Port-Channel 100:
SwitchA(config)# interface port-channel 100
SwitchA(config-if-po100)# switchport mode trunk
SwitchA(config-if-po100)# switchport trunk allowed vlan 101
SwitchA(config-if-po100)# exit
* Assign Physical Interfaces to Port-Channel 100:
SwitchA(config)# interface ethernet 1/5
SwitchA(config-if-eth1/5)# channel-group 100 mode active
SwitchA(config-if-eth1/5)# exit
SwitchA(config)# interface ethernet 1/6
SwitchA(config-if-eth1/6)# channel-group 100 mode active
SwitchA(config-if-eth1/6)# exit
* Configure MC-LAG Domain 1:
SwitchA(config)# mclag domain 1
SwitchA(config-mclag-domain)# peer-link port-channel 100
SwitchA(config-mclag-domain)# local-ip 192.168.1.1
SwitchA(config-mclag-domain)# peer-ip 192.168.1.2
SwitchA(config-mclag-domain)# system-mac 00:00:00:11:11:11
SwitchA(config-mclag-domain)# exit
* Save Configuration:
SwitchA# write memory
Comprehensive Detailed Step by Step Explanation with References:
* Enter Configuration Mode:
* Begin by entering the global configuration mode to make changes to the switch configuration.
* Create VLAN 101:
* Create VLAN 101 to be used for the MC-LAG peer link communication.
* Create Port-Channel 100:
* Enter the port channel interface configuration mode using interface port-channel 100.
* Set the port channel to trunk mode with switchport mode trunk.
* Allow VLAN 101 on the trunk with switchport trunk allowed vlan 101.
* Exit the port channel interface configuration mode.
* Assign Physical Interfaces to Port-Channel 100:
* Enter interface configuration mode for ethernet 1/5 and assign it to port channel 100 using the channel-group 100 mode active command.
* Exit the interface configuration mode.
* Repeat the same steps for ethernet 1/6.
* Configure MC-LAG Domain 1:
* Enter the MC-LAG domain configuration mode using mclag domain 1.
* Specify the peer link port channel with peer-link port-channel 100.
* Configure the local IP address as 192.168.1.1 using local-ip 192.168.1.1.
* Configure the peer IP address as 192.168.1.2 using peer-ip 192.168.1.2.
* Set the MC-LAG system MAC address using system-mac 00:00:00:11:11:11.
* Exit the MC-LAG domain configuration mode.
* Save Configuration:
* Save the configuration to ensure the changes persist after a reboot using the write memory command.
References:
* Dell Technologies Networking - SONiC
* Dell Enterprise SONiC Deployment Guide
These steps provide a comprehensive guide to configure the peer link for an MC-LAG scenario on SwitchA, ensuring the specific requirements for IP addressing, VLAN configuration, and port channel setup are met.

ECMP (Equal-Cost Multi-Path) is a Layer 3 routing feature that allows traffic to be forwarded using multiple available paths of equal cost. This improves bandwidth utilization and provides redundancy. ECMP is commonly used in modern networks to optimize the flow of traffic and increase the resiliency of network connections.
References:
* Dell Technologies SONiC documentation
* ECMP Configuration Guide