The experience of forgetting information that you trust a digital device to store and remember for you
Let’s ask ChatGPT to provide us the code for the following question: Can you generate a script that uses Netmiko and getpass to login to a list of devices (defined in a text file) using a Tacas account and run a specific command? Output the result into a csv file. Here’s the answer: Here is… read more »
Phase 1 Hub & Spoke Topology with EIGRP R1 R2 R3 R4 (Underlay)
When a router receives a multicast packet, RPF will check the routing table and check which interface it would use if it were to send traffic back to the multicast sender. If the interface matches the interface that the multicast packet was just received on, then the packet is accepted, otherwise it is dropped.
1.6c i Sparse Mode Instead of flooding multicast traffic to all potential receivers, PIM Sparse Mode builds explicit multicast distribution trees from the receivers to the sources. To build an explicit tree to the source, receivers and sources should have a way to dynamically discover each other – Rendezvous Points. The biggest challenge facing PIM… read more »
1.6.a i IGMPv2, IGMPv3 IGMP (Internet Group Management Protocol) is used to dynamically register individual hosts in a multicast group on a particular LAN. Hosts identify group membership by sending IGMP packets to their local multicast router. Under IGMP, routers listen to IGMP packets and periodically send queries to discover which groups are active/inactive on… read more »
1.5.e i Route reflector A route reflector is a BGP router that is allowed to ignore the iBGP loop avoidance rule and as such, is allowed to advertise updates received from an iBGP peer to another iBGP peer under specific conditions. The deployment of a route reflector can eliminate the BGP full-mesh requirement and greatly… read more »
1.5.f i Multipath, add-path BGP routers and route-reflectors propagate only their best path over their sessions. The advertisement of a prefix replaces the previous announcement of that prefix (known as an implicit withdraw). While this achieves better scaling, it comes at a cost of preventing path diversity. BGP additional path is a BGP extension that… read more »
1.5.d i local-as, allowas-in, remove-private-as Local AS Local AS configuration, essentially works the same way as the no-export community function, in that prefixes that are tagged are only advertised to neighbours within the same sub-AS, not to other sub-AS’ or eBGP peers. It allows a router to appear to be a member of a second… read more »
To decide which route is the best, each BGP router has a “best path selection” algorithm, where the information from two similar paths are compared. This is because it is not unusual for a BGP speaker to receive the same route from multiple peers. In fact, this is quite normal when you have multiple upstreams… read more »
BGP is an exterior gateway protocol, that is intended to be used between different autonomous systems. BGP is a path-vector protocol meaning it’s routes are composed of a list of AS’ on the path to any given destination. Routers running BGP are known as BGP ‘speakers’ and BGP neighbours are known as ‘peers’. If a… read more »