Classless & Classful Routing
DerekAustin26
Member Posts: 275
in CCNA & CCENT
Whats the difference?
Classless just use "IP Subnet Zero"
and Classful doesnt?
Am I understanding this correctly?
Classless just use "IP Subnet Zero"
and Classful doesnt?
Am I understanding this correctly?
Comments
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Xenz Member Posts: 140You're talking about classless and classful routing protocols? Classful (RIP/IGRP) do not send subnet masks, classless (RIPv2/EIGRP/OSPF) send subnet masks in their updates. ip subnet zero has nothing to do with this.Currently working on:
CCNP, 70-620 Vista 70-290 Server 2003
Packet Tracer activities and ramblings on my blog:
http://www.sbntech.info -
nutech444 Member Posts: 50 ■■□□□□□□□□Classless routing protocols are the protocols supporting Classless Inter-Domain Routing (CIDR), a newer scheme of IPv4 addressing. The mostly used Classless routing protocols include RIP v2 v3 and v4, EIGRP, OSPF, IS-IS and BGP4.
If a network address is subnetted, the first subnet obtained after subnetting the network address is called subnet zero.
Subnet Zero and the All-Ones Subnet [IP Addressing Services] - Cisco Systems
both are very imp concepts if you are working towards the ccna/ccent, cisco will most def test you on that, you have know this cold along with rest of the book ; ) -
Xenz Member Posts: 140Classless routing protocols are the protocols supporting Classless Inter-Domain Routing (CIDR), a newer scheme of IPv4 addressing. The mostly used classful routing protocols include RIP v2 v3 and v4, EIGRP, OSPF, IS-IS and BGP4.
If a network address is subnetted, the first subnet obtained after subnetting the network address is called subnet zero.
Subnet Zero and the All-Ones Subnet [IP Addressing Services] - Cisco Systems
both are very imp concepts if you are working towards the ccna/ccent, cisco will most def test you on that, you have know this cold along with rest of the book ; )
The protocols you listed are not classful unless you meant classless. Your definition of CIDR seems slightly off.Currently working on:
CCNP, 70-620 Vista 70-290 Server 2003
Packet Tracer activities and ramblings on my blog:
http://www.sbntech.info -
nutech444 Member Posts: 50 ■■□□□□□□□□yes its classless that was a typo thanks for pointing that out.
Here is a great guide on IP addressing
http://www.3com.com/other/pdfs/infra/corpinfo/en_US/501302.pdf -
DerekAustin26 Member Posts: 275You're talking about classless and classful routing protocols? Classful (RIP/IGRP) do not send subnet masks, classless (RIPv2/EIGRP/OSPF) send subnet masks in their updates. ip subnet zero has nothing to do with this.
So whats the difference between RIP/IGRP & RIPv2/EIGRP/OSPF ? RIP/IGRP uses distance vector while the latter uses Link-state? -
bubble2005 Member Posts: 210 ■■■□□□□□□□DerekAustin26 wrote: »So whats the difference between RIP/IGRP & RIPv2/EIGRP/OSPF ? RIP/IGRP uses distance vector while the latter uses Link-state?
RIP and IGRP are classful routing protocols that do not send subnet mask information with their routes. They are both distance vector protocols. RIPv2 is also a distance vector protocol however it is a classless distance vector protocol meaning that it sends subnet mask information with it's routes. Such subnet mask flexibility enables you to group several networks as a single entry in a routing table, significantly reducing routing overhead. OSPF is a link state classless routing protocol and EIGRP is a hybrid protocol, a mixture of link state and distance vector, however it is also classless routing protocol.Think Big Stay Focus: In the midst of all situations, think positive.:thumbup: -
Mark Knutson Member Posts: 73 ■■□□□□□□□□I just read a cidr rfc document and its been around for more than 12 years. I am wondering why we are learning classful stuff since its obsolete for the most part. I suppose its just considered simpler than going full cidr.
It helped me to put it in perspective reading about how cidr helps reduce the size of routing tables through summarization when the address structure corresponds to the physical topology of the internet. -
Xenz Member Posts: 140Mark Knutson wrote: »I just read a cidr rfc document and its been around for more than 12 years. I am wondering why we are learning classful stuff since its obsolete for the most part. I suppose its just considered simpler than going full cidr.
It helped me to put it in perspective reading about how cidr helps reduce the size of routing tables through summarization when the address structure corresponds to the physical topology of the internet.
No reason not to know the history of the Internet. RIP can still be used, IGRP I believe has been removed from IOS altogether. How do you make sense of CIDR/VLSM if you don't understand the need for it? There is also auto summary.Currently working on:
CCNP, 70-620 Vista 70-290 Server 2003
Packet Tracer activities and ramblings on my blog:
http://www.sbntech.info