PPP Encapsulation Changes Routing Table
Hey everyone...
Had another config question I wanted to throw out there...
I have (2) 2501s connected to each other's Serial1 interface.
R1 has been given the ip address 150.1.1.1 255.255.0.0 on its Serial 1 interface(with a clock rate as well)
R2 has been given the ip address 150.1.1.2 255.255.0.0 on its Serial 1 interface
I initially used HDLC between the routers and each router had this in its routing table:
C 150.1.0.0/16 is directly connected, Serial1
Then I decided to change the encapsulation on both routers to use PPP instead of HDLC. Immediately (on both routers) the routing table has changed to this:
R2#show ip route
Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2
i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
ia - IS-IS inter area, * - candidate default, U - per-user static route
o - ODR, P - periodic downloaded static route
Gateway of last resort is not set
150.1.0.0/16 is variably subnetted, 2 subnets, 2 masks
C 150.1.1.1/32 is directly connected, Serial1
C 150.1.0.0/16 is directly connected, Serial1
AND
R1#show ip route
Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2
i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
ia - IS-IS inter area, * - candidate default, U - per-user static route
o - ODR, P - periodic downloaded static route
Gateway of last resort is not set
C 150.1.1.2/32 is directly connected, Serial1
C 150.1.0.0/16 is directly connected, Serial1
It seems that using PPP has caused a /32 mask identifying the specific IP of the other router on that serial link. I searched through my running-config to make sure I didn't incorrectly configure an interface, but everything seems fine.
Does anyone know why this happens?
Thank you.
