Tuesday, March 18, 2014

CCDP - ARCH - Command Reference

This article looks to collect together the most frequent commands associated with the CCDP ARCH exam.

The point being that these are easy marks to pick up on the exam when you get a question such as 'Name the command that allows you to [insert task here]'

This list is by no means complete and I'll add further commands as I find them.

OSPF - Originate a default route in to OSPF
    #router ospf 10
        #default-information originate [always]

OSPF - On the ABR filter out all advertised routes accept those listed in the range command
Limits the size of the DB and reduces the flooding internally
    #router ospf 1
         #area 20 range 192.168.200.0 255.255.255.0

OSPF - On the ASBR filter routes sent out externally to those explicitly listed.
    #router ospf 20
         #summary address [prefix] [mask]

OSPF - Tune the OSPF hello timer interval for faster convergence
    #interface f0/0
        #ip ospf hello-interval [seconds]

OSPF - tune SPF timers to increase efficiency
    #conf t
          #timers throttle spf [spf-start] [spf-hold] [spf-max-wait]

OSPF - Increase the reference bandwidth to factor in high speed link such as 10GB ethernet, do this across all links for consistency
    #router ospf 20
          #auto-cost reference-bandwidth 10000 (for 10Gb ethernet links)

EIGRP - Originate a default route in to EIGRP
    #conf t
         #ip default-network [network ip]

EIGRP - configure unequal-cost load balancing
    #router eigrp 1
       #variance 2

BGP -configure neighbor as a Client of the route reflector
    #router bgp 65123
        #neighboor 1.1.1.1 route-reflector-client

IPv6 - enable IPv6 routing for use with RIPng, EIGRP for Ipv, OSPFv3 etc
    #conf t
         #ip v6 unicast-routing

IPv6 - Define a base prefix to use for addressing:
  #conf t
       #ipv6 general-prefix [prefix]

CEF - Eliminate CEF Polarisation where one redundant link ends up being preferred to the other
    #conf t
         #mls ip cef load-sharing

EtherChannel - Use this to ensure all links within an Etherchannel bundle are utilised effectiviely
    #conf t
        #port-channel load-balance src-dst-port

FlexLinks  - Configure a port to act as a resilient backup for FlexLinks. Configure this on the primary link.
    #interface f0/10
       #switchport backup-interface [interface id]

Friday, March 7, 2014

CCDP - ARCH - Well Known Multicast Addresses

In the CCDP ARCH exam there are numerous refereences to Multicast addresses.

This post is to simply catalogue those that are specifically refered to in the various reading materials I've covered.

Address Scope:
  • 224.0.0.0 /4 - Class D reservation
Address type:
  • 224.0.0.0 to 224.0.0.255 - assigned by IANA for services (detailed below)
  • 224.0.1.0 to 224.0.1.255 - Control Block - assigned by IANA for traffic crossing public networks e.g.- NTP 224.0.1.1
  •  224.0.2.0 to 224.0.255.255 - AD-HOC block assigned by IANA for addresses that don't fit the above ranges
  • 224.3.0.0 to 224.4.255.255 - AD-HOC block assigned by IANA for addresses that don't fit the above ranges
  • 233.252.0.0 to 233.255.255.255-  AD-HOC block assigned by IANA for addresses that don't fit the above ranges
  • 232.0.0.0 255.0.0.0 - Source-Specfic Multicast Addresses
  • 233.0.0.0 255.0.0.0 - GLOP addresses - Originally experimental now publically assigned addresses for use by ISPs and any organisation want to ublich content over Multicast
  • 234.0.0.0 255.0.0.0 - Uni-cast Prefix addresses
  • 239.0.0.0 255.0.0.0 - Administratively scoped IPv4 addresses, locally assigned, not globally unique
Well Known Addresses:


  • 224.0.0.1 The All Hosts multicast group addresses all hosts on the same network segment.

  • 224.0.0.2 The All Routers multicast group addresses all routers on the same network segment.

  • 224.0.0.5 The Open Shortest Path First (OSPF) All OSPF Routers address is used to send Hello packets to all OSPF routers on a network segment.

  • 224.0.0.6 The OSPF All Designated Routers ""(DR)"" address is used to send OSPF routing information to designated routers on a network segment.

  • 224.0.0.9 The Routing Information Protocol (RIP) version 2 group address is used to send routing information to all RIP2-aware routers on a network segment.

  • 224.0.0.10 The Enhanced Interior Gateway Routing Protocol (EIGRP) group address is used to send routing information to all EIGRP routers on a network segment.

  • 224.0.0.13 Protocol Independent Multicast (PIM) Version 2

  • 224.0.0.18 Virtual Router Redundancy Protocol (VRRP)

  • 224.0.0.19 - 21 IS-IS over IP

  • 224.0.0.22 Internet Group Management Protocol (IGMP) version 3

  • 224.0.0.102 Hot Standby Router Protocol version 2 (HSRPv2) / Gateway Load Balancing Protocol (GLBP)

  • 224.0.1.1 Network Time Protocol clients listen on this address for protocol messages when operating in multicast mode.

  • 224.0.1.39 The Cisco multicast router AUTO-RP-ANNOUNCE address is used by RP mapping agents to listen for candidate announcements.

  • 224.0.1.40 The Cisco multicast router AUTO-RP-DISCOVERY address is the destination address for messages from the RP mapping agent to discover candidates.

  • 224.0.1.41 H.323 Gatekeeper discovery address

  • 239.255.255.250 Simple Service Discovery Protocol address




  •