| Author |
HDLC Multipoint Support!
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| nhesson 2002-08-22, 7:22 pm |
| Does HDLC support Multipoint?
Cisco Press CCNA book does not say anything about HDLC being Multipoint protocol.
Thanks for your help!
Nick | |
| darthfeces 2002-08-22, 10:02 pm |
| hdlc is merely a data-link encapsulation
on top of that on a serial interface you can
have
point to point interface
subinterfaces
point to point
multipoint
so i guess the answer is yes
although it's not related in the way you think.
(config-if)#encapsulation ?
atm-dxi ATM-DXI encapsulation
bstun Block Serial tunneling (BSTUN)
frame-relay Frame Relay networks
hdlc Serial HDLC synchronous
lapb LAPB (X.25 Level 2)
ppp Point-to-Point protocol
sdlc SDLC
sdlc-primary SDLC (primary)
sdlc-secondary SDLC (secondary)
smds Switched Megabit Data Service (SMDS)
stun Serial tunneling (STUN)
x25 X.25 | |
| nhesson 2002-08-23, 12:17 am |
| Yes, I know HDLC is a encapsulation, but only for a two node point-to-point connection? HDLC encapsulation does not support a multi node network? Does it??
Only reason way I ask, is for a test question. Saying that HDLC supports a multipoint network.
But HDLC does not support interface addressing, so there is no way to support MultiAccess?
Thanks for your help.
Nick | |
| darthfeces 2002-08-23, 5:56 pm |
| yes, it does
in a short explanation
conceptually your off base
encapsulation or "data link" encapsulation is layer two
interface addressing is layer 3
so the interface type is seperate and unrelated
to the layer two encapsulation.
this is why we have split-horizon issues on nbma
networks. because layer 3 routing has no knowledge
of the layer 2 data link and frames may need
to be sent in and out of the same subinterface
that layer 3 routing is not aware of.
if this still does not make sense to you maybe someone else could explain. ? | |
| Yankee 2002-08-24, 5:41 am |
| Everything Darth says is 100% technically correct but my only concern on it working in reality is if there is a device similar to a frame-switch to separate the signals from a single T1. To my knowledge there is no such device, so I would think in reality the answer is no while as Darth states technically there is no reason it can't be designed.
I'm sure some one will correct me if I'm way off base...
Yankee | |
| MadChef 2002-08-24, 6:25 am |
| quote:
Originally posted by Yankee
Everything Darth says is 100% technically correct but my only concern on it working in reality is if there is a device similar to a frame-switch to separate the signals from a single T1. To my knowledge there is no such device
What about using HDLC as the encapsulation for ISDN? Then everything is switched at the phone switch. Seems like that would apply.
Thoughts?
MadChef | |
| nhesson 2002-08-24, 9:14 pm |
| Well, once again HDLC is a layer 2 protocol. But with Frame-relay, 802.3, and 802.5, guess what? ALL THEM HAVE ADDRESSING!!! HDLC does not use layer 3 addressing to make encapsulation decidtions. ALL MULTIACCESS networks Layer 2 HAS to have addressing. How does a node know that another node is talking to it or not? If you have three router using HDLC connecting to ?WHAT? one T1??? There is my point! How can you have three nodes runing HDLC in one network??????
Nick | |
| Yankee 2002-08-25, 4:51 am |
| quote:
Originally posted by MadChef
What about using HDLC as the encapsulation for ISDN? Then everything is switched at the phone switch. Seems like that would apply.
Thoughts?
MadChef
I guess that technically would be point to multipoint, MC, you clever guy!
Yankee |
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