Wassim

Just like you wear a watch to have time, network devices have a time protocol called NTP that does just that. The following are my study notes on the subject. There are two types of clocks: hardware clock and software clock. The hardware clock has its own battery. When router shuts down, hardware calendar still works. When we reboot router, the software clock synchronizes with hardware clock, even if we already set the software clock. Once the software clock is user-defined, we can synchronize the hardware clock with it, with “clock update-calendar”. with “show clock” and “show clock detail”, if an asterisk is displayed then the time server is not authoritative which means that it is not reliable. The protocol has a notion of stata . Each time server has a stratum: Server with stratum 0 has more precise time than server with stratum 1, etc. Server with stratum 1 feeds server with stratum 2, which feeds server with stratum 3, etc. NTP synchronises sof...

We learn in this post how to configure route redistribution between OSPF, EIGRP, BGP and static routes. The first section depicts OSPF route redistribution into EIGRP. The second section gives an example of redistributing static routes into EIGRP. And lastly we see an example of redistributing BGP into OSPF. Injecting OSPF prefixes into EIGRP – On the ASBR, and after redistribution, there’s a change in EIGRP topology table. But no changes happen in the routing table: before redistribution: after redistribution: The change happens on the other routers, i.e. DSW1 and DSW2. Redistribute ospf match internal Before this command, here’s DSW1 RIB: Then: The 10.1.1.8 prefix is a subnet that’s internal to OSPF, i.e. it was not redistributed into OSPF before arriving to R4. The 0.0.0.0/0 is also an OSPF Internal route (the default route that’s injected by R3 into the totally stub NSSA) . So it is redistributed into EIGRP too. “redistribute ospf ..”, wit...