Connecting to the lab server

• Open your favourite Terminal Emulator
• SSH to the netlab server:

• $ ssh-keygen -R netlab.nanocat.net   <- delete the cached fingerprint
                                          (lab server rebuilt frequently)
  $ ssh lab@netlab.nanocat.net
  Password: (generated fresh each week)
  

• List the running containerlab devices:

• $ sudo containerlab inspect --all
  

• Connect to an Arista device:

• $ sudo docker exec -it clab-device–name Cli
  

• .. or connect to a Linux device:

• $ sudo docker exec -it clab-pcXX-name bash
  

Diagram

Goal

• all devices in all VLANs can ping each other.

Multi-Layer Switching (MLS)

• Old Think: Switches = Layer 2, Routers = Layer 3
• New Think: “switching” and “routing” are roles
• Switching = forwarding packets at Layer 2
  • Frames (sometimes called “Layer 2 Packets”)
  • forwarding based on destination MAC address (show mac address-table)
  • no IP addresses (show ip interface brief)
  • no participation in routing (show ip route)
• Routing = forwarding packets at Layer 3
  • Packets
  • forwarding based on destination IP address (show ip route)
    • or label when using MPLS
  • IPv4: ARP (Address Resolution Protocol) (show ip arp)
  • IPv6: NDP (Neighbor Discovery Protocol) (show ipv6 neighbors)
  • routing table (show ip route)

Configuration overview

• Create a Layer 3 VLAN interface to act as the gateway for your PCs
• Ensure your PCs have the correct default route set

What you are responsible for configuring

• the two PCs connected to your switch
• your switch (switch-XX)
• your uplink port on core-01
• the L3 VLAN interface as follows:
  • switch-01: vlan 10
  • switch-02: vlan 20
  • switch-03: vlan 30
  • switch-04: vlan 40
  • switch-05: vlan 50

Convert the core-01 into a Multi-Layer Switch

!
ip routing
!

Configure a Layer 3 VLAN interface

!
interface vlan 10
   description --- web ---
   ip address 192.168.10.1/24
!

Inspect core-01

show mac address-table
show ip arp
show ip route
ping 192.168.x.x

tcpdump

At a bash prompt:

# capture and decode all packets on ethX
$ tcpdump -i ethX

# capture and decode all ICMP packets on ethX
$ tcpdump -i ethX icmp

# capture and decode all packets to or from 192.168.100.100
$ tcpdump -i ethX host 192.168.100.100

# capture and decode FRAMES
$ tcpdump -i ethX -e ether

# capture and decode FRAMES with a filter
$ tcpdump -i ethX -e ether host 01:23:45:67:89:01