CCIE – RS – L3 Technologies – Addressing Technologies – IPv4

In this section I assume that you have a CCNA level of understanding of IP addressing

Identify, Implement and Troubleshoot IPv4 Addressing and Subnetting

Address Types

Class A: to

Private range: –

Class B: to

Private range: to

Class C: to

Private range: to

Class D: to

Class E: to


Variable Length Subnet Mask

Allows for dividing ip addresses into subnets of different sizes

I make the following table before doing any subnetting math. This will help you figure out what the /cidr into subnet mask numbers will be without much effort. This will then help you figure out the network and broadcast range.

Screen Shot 2018-01-28 at 8.33.15 PM.png

Subnet Math: What are the network and broadcast addresses of the following range

/28 =

Network –, Broadcast

/19 =

Network –, Broadcast


Address Resolution Protocol

  • RFC 826
  • Protocol so that IP hosts can discover the MAC address of another device
  • L3 needs ARP to map IP network addresses to MAC hardware addresses so IP packets can be sent across networks
  • Cisco routers hold ARP entries for 4 hours by default
    • This can be changed under interface configuration: arp timeout ###

Proxy ARP

  • Allow L3 device to respond on behalf of actual destination for ARP
  • RFC 925 and 1027
  • Router makes itself available to hosts as a “gateway”
    • If a host is missing it’s default gateway the router will act as this
  • Enabled by default: disable on interface with – no ip proxy-arp

Reverse ARP (RARP)

  • Host attempting to find its own IP address, replaced DHCP
  • Maps IP address to known hardware address

CCIE RS – Describe WAN Rate-based Ethernet Circuits – Metro and WAN Ethernet Topologies


  • Enables carriers to bring various WAN connections (IP or MPLS) together in a single logical ethernet network
  • Allows MPLS networks to provide multipoint ethernet services
  • Allow CE nodes to communicate directly with other CE nodes
  • Ethernet Bridges – Pseudo-Wires (PW)
  • Forwards frames at L2
  • Self-learn source MAC address to port and frames are forwarded based on destination MAC address
    • If MAC is unknown, broadcast or multicast is flooded out all ports associated with virtual bridge
  • Architecture must perform
    • Auto discover other PE’s associated with the VPLS instance
    • Signaling of PWs to interconnect VPLS virtual Switch Instance (VSI)
    • Loop avoidance
    • MAC address withdrawal


  • • Separated into different subsections
    • Port-based
    • Per-vlan
    • Per-class per-vlan



Ethernet private line (EPL) (for example, Ethernet mapped to SONET/SDH frames) or Ethernet Internet access with IPsec encryption (no split tunnel)


Ethernet Virtual Private Line (EVPL), also called Ethernet Relay Service (ERS)




Ethernet Internet access with multipoint DMVPN or MPLS Ethernet access to group encrypted transport (GET)


Ethernet Relay Multipoint Service (ERMS) or Ethernet Multipoint Service (EMS)



Carrier Ethernet Services

  • Ethernet Virtual Private Line – E-LINE

    • Connect 2 customer ethernet ports over a WAN
    • Ethernet Private Line (EPL)
      • Provide p2p ethernet virtual connection (EVC) between a pair of user network interfaces (UNIs)
      • High degree of transparency
    • ○ Ethernet Virtual Private Line (EVPL)
      • Provide p2p or p2m between a pair of UNIs
  • Ethernet Virtual Private LAN – E-LAN

    • Multipoint service connecting sets of customer endpoints
    • Appearance of a bridged ethernet connecting the sites
  • Ethernet Virtual Private Tree – E-TREE

    • Multipoint service connecting one or more root to a set of leaves