3.1.a (ii) ARP From within the same LAN we need a reliable way to map IP addresses to MAC addresses. The way ARP works is we send out a request which goes out as an ethernet broadcast, to all hosts on the broadcast domain. The dst mac this is sent to is ffff.ffff.ffff. This request …
Category Archives: CCIE R&S
3.1.a (i) Address types, VLSM
3.1.a (i) Address types, VLSM For this section you should understand the basics of IPv4 addressing. We should remember that an IPv4 address is a 32bit number with a max of about 4 billion. It’s written in dotted decimal notation like so 10.0.0.1 Each number separated by a decimal is 1 byte in size. …
2.1.g (i) SPAN, RSPAN, ERSPAN
2.1.g (i) SPAN, RSPAN, ERSPAN SPAN What problem does it solve? Switchport analyzer (SPAN) We need visibility on the traffic coming into our LAN. We have a network monitor device that we want to send copies of the frames to. SPAN ports allow you to mirror a port to another one so you can capture …
2.1.f (iv) Loopguard, Rootguard
2.1.f (iv) Loopguard, Rootguard RootGuard Root guard makes sure that if we receive a superior BPDU on certain ports that we don’t trust them, and we can put the port into blocking state. Root guard should be enabled on “edge” or access ports. It’s usually accompanied by portfast. When a superior BPDU comes in, our …
2.1.f (iii) Portfast, BPDUguard, BPDUfilter
2.1.f (iii) Portfast, BPDUguard, BPDUfilter PortFast With RSTP this is now an open standard and is called an EDGE port, however the configuration is still very similar to 802.1d portfast Allows a port running STP to go from blocking to forwarding immediately. This skips listening and learning (15 + 15 sec) Should only be enabled …
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2.1.f (i) PVST+/RPVST+/MST
2.1.f (i) PVST+/RPVST+/MST 802.1D Classic STP and PVST+ Note that when focusing on legacy spanning tree, we are actually focusing on per vlan spanning tree + which runs classic STP per vlan. We don’t actually have the option of 802.1D or classic spanning-tree in our switches. Before we begin you should know what a burned …