AG

CCNA Knowledge

  • FF01::1 Node-local Same node FF02::1 Link-local All nodes on a link FF01::2 Node-local Same router FF02::2 Link-local All routers on a link FF05::2LLDP - Link Layer Discovery Protocol - A protocol used for network devices to advertise their identity and capabilities on a local area network (LAN). - Runs on Layer 2 (Switches Bridges). Disabled by default on Cisco switches.

    • Can be configured to disable either send or receive LLDP packets

    • Cisco commands

      • to view - show lldp interface (interface)

      • transmit/receive - enter interface config: no lldp receive or no lldp transmit

      • enable globally - lldp run

  • VTP - VLAN Trunking Protocol - A Cisco proprietary protocol that manages VLANs on a network, allowing for the configuration of multiple switches to share VLAN information.

  • IPV6

    • EUI-64 Method - Embedding the MAC into the IPV6 address

      • in a /64 format, converts a mac address by splitting the mac address (6 sets) into 3 and 3 and then putting “FF FE” in the middle

        • Example: MAC: 001F:9EFC:7AD0 in a 2012:ABC::/64

          • Becomes 2012:ABC::21F:9EFF:FEFC:7AD0 (inverted the 7th bit of the first octet 00 to 02 if only locally unique)

    • An IPV6 interface has Unicast, Multicast, and Anycast address

      • link local, unique local, global

      • Reserved:

        • Link local starts with FE80::/10

        • FF01,02,05,08, and 0E /16 are multicast scopes

    • 8 sets of 16 bit hexadecimal values separated by “:” colon | 4 values per set

    • In network prefix, like ipv4, 2001:db8:12::/64 for example: /64 is the first 64 bits (each set is 16 bits, so 4 sets) are the network ID portion and the rest the Host ID

      • Leading zeros are removed: 2001:0db8:0012::/64

      • :: means leading zeroes so 2001:0db8:0012:0000::/64

  • IP Helper-address - Cisco command which helps forward DHCP packets that are in another network.

    • Use: If device on RouterA needs IP from DHCP on RouterB

      • RouterA(config-if)#ip helper-address (ip of the DHCP server)

  • Layer 3 - Routers -Do not forward broadcast traffic

    • Control Plane - the “brains” of the router, determines how to move traffic

  • Cisco ACI Architecture - Spine and leaf topology

    • APIC - Application Policy Manager - connected to leaf-switches

    • Spines connect fast speed transfer among leaf switches

  • Cisco Lightweight AP Modes

    • Local Mode - Normal connectivity for the client, acts like standard AP

    • FlexConnect - Can work independent from the WLC (Wireless Lan Controller), local switching, normal connection.

    • Bridge - Mesh mode where it extends other APs

    • Monitor Mode - Scans nearby wifi signal for monitoring, no connectivity

    • Rogue Detector - Turns off radio and focuses purely on finding foreign devices on the network using ARP and MACs

    • Sniffer Mode - Captures packets and forwards for analysis

  • RSTP - Rapid Spanning Tree Protocol

    • Ports

      • Root - Shortest pass to the root bridge

      • Designated - Forwards traffic to root bridge

      • Alternate - alternate for the root

      • Backup - alternate for Designated port

    • OSPF - Open shortest path first

      • supports qual-cost load balancing.

    • Cisco DNA - Digital Network Architecture Center - Cisco management solution that uses SDA (software defined access)

    • Root guard - prevents the new unconfigured switch from being the root switch