Newbie: async mode dedicated versus async mode interactive!!

Discussion in 'Cisco' started by Pink_Floyd, Jun 9, 2006.

  1. Pink_Floyd

    Pink_Floyd Guest

    Hi All,

    Good Evening!!

    I have been trying to understand the difference between async mode
    dedicated and async mode interactive and have searched the group for
    some answers. I have also read Cisco's documentation and have gained
    little understanding from it. I would appreciate your time and effort
    if you could please help me clarify the issue.

    One chain of thought indicates that if we use async mode dedicated,
    then the interface starts functioning in framed mode (SLIP / PPP). If
    we use async mode interactive, then the user has the liberty to use
    TELNET.

    Now SLIP / PPP are L2 protocols while TELNET is an L4 protocol So I
    found this explanation hard to follow.

    My understanding is that if we use the interactive mode, then the end
    user has the option of accessing the exec prompt. Am I correct? Also,
    what is the significance of the dedicated mode?

    Regards,
    - PinkFloyd
     
    Pink_Floyd, Jun 9, 2006
    #1
    1. Advertising

  2. Hi Pink,

    ~ I have been trying to understand the difference between async mode
    ~ dedicated and async mode interactive and have searched the group for
    ~ some answers. I have also read Cisco's documentation and have gained
    ~ little understanding from it. I would appreciate your time and effort
    ~ if you could please help me clarify the issue.
    ~
    ~ One chain of thought indicates that if we use async mode dedicated,
    ~ then the interface starts functioning in framed mode (SLIP / PPP).

    This is so.

    ~ If
    ~ we use async mode interactive, then the user has the liberty to use
    ~ TELNET.

    This is so.

    ~ Now SLIP / PPP are L2 protocols while TELNET is an L4 protocol

    This is so.

    ~ So I found this explanation hard to follow.
    ~
    ~ My understanding is that if we use the interactive mode, then the end
    ~ user has the option of accessing the exec prompt. Am I correct?

    You are.

    ~ Also,
    ~ what is the significance of the dedicated mode?

    As you way, in dedicated mode, when the interface comes up, it is in
    framed mode (SLIP/PPP). When the interface comes up, it is in UNFRAMED
    async mode.

    So what you may be missing is an understanding of what unframed async
    mode is. Perhaps it would be more helpful to describe it as "character-at-
    a-time mode"? When a line is operating in unframed async mode, then when
    the router receives a character from the line, it will not treat it as part
    of a layer 2 frame, but as a character to be input to the exec process.

    For example, let's say that the line is operating in unframed async mode,
    and that it receives the following data pattern from the line:

    7368 6f77 2076 6572 7369 6f6e 0d

    Let's say that the exec process on the line is sitting at the exec mode
    prompt ("router#"). Then, when the router receives that data pattern
    from the line, it will parse it as ASCII, so it will see it as:
    "show version\r"
    and so it will respond by transmitting the "show version" output.

    Now, let's say that the line is operating in framed async (let's say, PPP)
    mode, and receives the same data pattern. It will attempt to parse
    this pattern as an async PPP frame - but since this is an invalid frame,
    the receiver will discard the data, and one of the input error counters
    in "show interface async<n>" will increment.

    Does this make it clearer?

    Aaron
     
    Aaron Leonard, Jun 9, 2006
    #2
    1. Advertising

  3. Pink_Floyd

    Pink_Floyd Guest

    Hi Aaron,

    Good Evening!!

    Thank you for your help on the issue.

    Yes your answer did help me to understand the difference.

    However, I have one question that lingers in my mind.

    Even if the line is configured to interpret stuff in character mode,
    won't my PC send stuff through Layer 2 which will eventually be
    encapsulated appropriately? (Thus even if I used TELNET, it would
    eventually be encapsulated that L2 protocol.)

    Please advise.

    Regards,
    - Pink_Floyd

    Aaron Leonard wrote:
    > Hi Pink,
    >
    > ~ I have been trying to understand the difference between async mode
    > ~ dedicated and async mode interactive and have searched the group for
    > ~ some answers. I have also read Cisco's documentation and have gained
    > ~ little understanding from it. I would appreciate your time and effort
    > ~ if you could please help me clarify the issue.
    > ~
    > ~ One chain of thought indicates that if we use async mode dedicated,
    > ~ then the interface starts functioning in framed mode (SLIP / PPP).
    >
    > This is so.
    >
    > ~ If
    > ~ we use async mode interactive, then the user has the liberty to use
    > ~ TELNET.
    >
    > This is so.
    >
    > ~ Now SLIP / PPP are L2 protocols while TELNET is an L4 protocol
    >
    > This is so.
    >
    > ~ So I found this explanation hard to follow.
    > ~
    > ~ My understanding is that if we use the interactive mode, then the end
    > ~ user has the option of accessing the exec prompt. Am I correct?
    >
    > You are.
    >
    > ~ Also,
    > ~ what is the significance of the dedicated mode?
    >
    > As you way, in dedicated mode, when the interface comes up, it is in
    > framed mode (SLIP/PPP). When the interface comes up, it is in UNFRAMED
    > async mode.
    >
    > So what you may be missing is an understanding of what unframed async
    > mode is. Perhaps it would be more helpful to describe it as "character-at-
    > a-time mode"? When a line is operating in unframed async mode, then when
    > the router receives a character from the line, it will not treat it as part
    > of a layer 2 frame, but as a character to be input to the exec process.
    >
    > For example, let's say that the line is operating in unframed async mode,
    > and that it receives the following data pattern from the line:
    >
    > 7368 6f77 2076 6572 7369 6f6e 0d
    >
    > Let's say that the exec process on the line is sitting at the exec mode
    > prompt ("router#"). Then, when the router receives that data pattern
    > from the line, it will parse it as ASCII, so it will see it as:
    > "show version\r"
    > and so it will respond by transmitting the "show version" output.
    >
    > Now, let's say that the line is operating in framed async (let's say, PPP)
    > mode, and receives the same data pattern. It will attempt to parse
    > this pattern as an async PPP frame - but since this is an invalid frame,
    > the receiver will discard the data, and one of the input error counters
    > in "show interface async<n>" will increment.
    >
    > Does this make it clearer?
    >
    > Aaron
     
    Pink_Floyd, Jun 12, 2006
    #3
  4. On 11 Jun 2006 17:27:30 -0700, "Pink_Floyd" <> wrote:

    > Hi Aaron,
    > Good Evening!!
    >
    > Thank you for your help on the issue.
    >
    > Yes your answer did help me to understand the difference.
    >
    > However, I have one question that lingers in my mind.
    >
    > Even if the line is configured to interpret stuff in character mode,
    > won't my PC send stuff through Layer 2 which will eventually be
    > encapsulated appropriately?


    Nope! If the PC is operating in character mode, then it doesn't use any framing protocol.

    > (Thus even if I used TELNET, it would
    > eventually be encapsulated that L2 protocol.)
    >


    I guess a picture might help ...


    [TELNET server]-----{IP network}-----[router [TELNET client]]--async line--[PC]
    |<---------------------------- character stream ---------------------------->|
    ||<------------------- TELNET session ------------------>|<-unframed async->||
    |||<--------------------TCP connection ---------------->||

    Does this help?

    Aaron

    ---

    > Please advise.
    >
    > Regards,
    > - Pink_Floyd
    >
    > Aaron Leonard wrote:
    >
    >> Hi Pink,
    >>
    >> ~ I have been trying to understand the difference between async mode
    >> ~ dedicated and async mode interactive and have searched the group for
    >> ~ some answers. I have also read Cisco's documentation and have gained
    >> ~ little understanding from it. I would appreciate your time and effort
    >> ~ if you could please help me clarify the issue.
    >> ~
    >> ~ One chain of thought indicates that if we use async mode dedicated,
    >> ~ then the interface starts functioning in framed mode (SLIP / PPP).
    >>
    >> This is so.
    >>
    >> ~ If
    >> ~ we use async mode interactive, then the user has the liberty to use
    >> ~ TELNET.
    >>
    >> This is so.
    >>
    >> ~ Now SLIP / PPP are L2 protocols while TELNET is an L4 protocol
    >>
    >> This is so.
    >>
    >> ~ So I found this explanation hard to follow.
    >> ~
    >> ~ My understanding is that if we use the interactive mode, then the end
    >> ~ user has the option of accessing the exec prompt. Am I correct?
    >>
    >> You are.
    >>
    >> ~ Also,
    >> ~ what is the significance of the dedicated mode?
    >>
    >> As you way, in dedicated mode, when the interface comes up, it is in
    >> framed mode (SLIP/PPP). When the interface comes up, it is in UNFRAMED
    >> async mode.
    >>
    >> So what you may be missing is an understanding of what unframed async
    >> mode is. Perhaps it would be more helpful to describe it as "character-at-
    >> a-time mode"? When a line is operating in unframed async mode, then when
    >> the router receives a character from the line, it will not treat it as part
    >> of a layer 2 frame, but as a character to be input to the exec process.
    >>
    >> For example, let's say that the line is operating in unframed async mode,
    >> and that it receives the following data pattern from the line:
    >>
    >> 7368 6f77 2076 6572 7369 6f6e 0d
    >>
    >> Let's say that the exec process on the line is sitting at the exec mode
    >> prompt ("router#"). Then, when the router receives that data pattern
    >> from the line, it will parse it as ASCII, so it will see it as:
    >> "show version\r"
    >> and so it will respond by transmitting the "show version" output.
    >>
    >> Now, let's say that the line is operating in framed async (let's say, PPP)
    >> mode, and receives the same data pattern. It will attempt to parse
    >> this pattern as an async PPP frame - but since this is an invalid frame,
    >> the receiver will discard the data, and one of the input error counters
    >> in "show interface async<n>" will increment.
    >>
    >> Does this make it clearer?
    >>
    >> Aaron
    >>
     
    Aaron Leonard, Jun 12, 2006
    #4
  5. Pink_Floyd

    Pink_Floyd Guest

    Hi Aaron,

    Apologies for the delayed reply.

    Yes that indeed helped.

    Thank you for your time and effort in helping me out.

    Warm Regards,

    - Pink_Floyd
    Aaron Leonard wrote:
    > On 11 Jun 2006 17:27:30 -0700, "Pink_Floyd" <> wrote:
    >
    > > Hi Aaron,
    > > Good Evening!!
    > >
    > > Thank you for your help on the issue.
    > >
    > > Yes your answer did help me to understand the difference.
    > >
    > > However, I have one question that lingers in my mind.
    > >
    > > Even if the line is configured to interpret stuff in character mode,
    > > won't my PC send stuff through Layer 2 which will eventually be
    > > encapsulated appropriately?

    >
    > Nope! If the PC is operating in character mode, then it doesn't use any framing protocol.
    >
    > > (Thus even if I used TELNET, it would
    > > eventually be encapsulated that L2 protocol.)
    > >

    >
    > I guess a picture might help ...
    >
    >
    > [TELNET server]-----{IP network}-----[router [TELNET client]]--async line--[PC]
    > |<---------------------------- character stream ---------------------------->|
    > ||<------------------- TELNET session ------------------>|<-unframed async->||
    > |||<--------------------TCP connection ---------------->||
    >
    > Does this help?
    >
    > Aaron
    >
    > ---
    >
    > > Please advise.
    > >
    > > Regards,
    > > - Pink_Floyd
    > >
    > > Aaron Leonard wrote:
    > >
    > >> Hi Pink,
    > >>
    > >> ~ I have been trying to understand the difference between async mode
    > >> ~ dedicated and async mode interactive and have searched the group for
    > >> ~ some answers. I have also read Cisco's documentation and have gained
    > >> ~ little understanding from it. I would appreciate your time and effort
    > >> ~ if you could please help me clarify the issue.
    > >> ~
    > >> ~ One chain of thought indicates that if we use async mode dedicated,
    > >> ~ then the interface starts functioning in framed mode (SLIP / PPP).
    > >>
    > >> This is so.
    > >>
    > >> ~ If
    > >> ~ we use async mode interactive, then the user has the liberty to use
    > >> ~ TELNET.
    > >>
    > >> This is so.
    > >>
    > >> ~ Now SLIP / PPP are L2 protocols while TELNET is an L4 protocol
    > >>
    > >> This is so.
    > >>
    > >> ~ So I found this explanation hard to follow.
    > >> ~
    > >> ~ My understanding is that if we use the interactive mode, then the end
    > >> ~ user has the option of accessing the exec prompt. Am I correct?
    > >>
    > >> You are.
    > >>
    > >> ~ Also,
    > >> ~ what is the significance of the dedicated mode?
    > >>
    > >> As you way, in dedicated mode, when the interface comes up, it is in
    > >> framed mode (SLIP/PPP). When the interface comes up, it is in UNFRAMED
    > >> async mode.
    > >>
    > >> So what you may be missing is an understanding of what unframed async
    > >> mode is. Perhaps it would be more helpful to describe it as "character-at-
    > >> a-time mode"? When a line is operating in unframed async mode, then when
    > >> the router receives a character from the line, it will not treat it as part
    > >> of a layer 2 frame, but as a character to be input to the exec process.
    > >>
    > >> For example, let's say that the line is operating in unframed async mode,
    > >> and that it receives the following data pattern from the line:
    > >>
    > >> 7368 6f77 2076 6572 7369 6f6e 0d
    > >>
    > >> Let's say that the exec process on the line is sitting at the exec mode
    > >> prompt ("router#"). Then, when the router receives that data pattern
    > >> from the line, it will parse it as ASCII, so it will see it as:
    > >> "show version\r"
    > >> and so it will respond by transmitting the "show version" output.
    > >>
    > >> Now, let's say that the line is operating in framed async (let's say, PPP)
    > >> mode, and receives the same data pattern. It will attempt to parse
    > >> this pattern as an async PPP frame - but since this is an invalid frame,
    > >> the receiver will discard the data, and one of the input error counters
    > >> in "show interface async<n>" will increment.
    > >>
    > >> Does this make it clearer?
    > >>
    > >> Aaron
    > >>
     
    Pink_Floyd, Jun 16, 2006
    #5
    1. Advertising

Want to reply to this thread or ask your own question?

It takes just 2 minutes to sign up (and it's free!). Just click the sign up button to choose a username and then you can ask your own questions on the forum.
Similar Threads
  1. AAH

    Interactive and non interactive

    AAH, Jan 9, 2005, in forum: Computer Support
    Replies:
    1
    Views:
    644
  2. AAH

    non Interactive and Interactive

    AAH, Jan 9, 2005, in forum: Computer Support
    Replies:
    0
    Views:
    814
  3. =?Utf-8?B?Q2FuYWRhX0d1eU0=?=

    Certification - MCP versus MCSA versus MCSE

    =?Utf-8?B?Q2FuYWRhX0d1eU0=?=, Aug 24, 2006, in forum: Microsoft Certification
    Replies:
    1
    Views:
    774
    =?Utf-8?B?TW9udHJlYWwgTUNTQQ==?=
    Aug 24, 2006
  4. Replies:
    3
    Views:
    653
  5. Peter Potamus the Purple Hippo

    Re: Mozilla versus IE versus Opera versus Safari

    Peter Potamus the Purple Hippo, May 8, 2008, in forum: Firefox
    Replies:
    0
    Views:
    811
    Peter Potamus the Purple Hippo
    May 8, 2008
Loading...

Share This Page