Is it possible to simultaneously transmit a basic ring topology?

Question

Is it possible to simultaneously transmit with a basic ring topology? In a basic ring topology can I have more than one token? Is Active Monitor will remove tokens if I have more then one? Can you give some useful link about it?

Answer 1

Well it depends on what kind of ring we are talking about. If the ring is able to use multiple wavelengths, such as a MultiTokenRing, then it can have one token per wavelength, and thus multiple nodes can transmit data at the same time.

For a simple ring, I think Wikipedia has a clear answer:

When no station is transmitting a data frame, a special token frame circles the loop. This special token frame is repeated from station to station until arriving at a station that needs to transmit data. When a station needs to transmit data, it converts the token frame into a data frame for transmission. Once the sending station receives its own data frame, it converts the frame back into a token. If a transmission error occurs and no token frame, or more than one, is present, a special station referred to as the Active Monitor detects the problem and removes and/or reinserts tokens as necessary (see Active and standby monitors). On 4 Mbit/s Token Ring, only one token may circulate; on 16 Mbit/s Token Ring, there may be multiple tokens.

Answer 2

There are two methods:

1) Single-token method

After capturing the token, the source sends a "busy token" followed by its data. The token is released back as a "free token" only after the busy token is received back by the source.

2) Multi-token method

The free token is attached at the end of the data. At one time, there can be multiple busy tokens but only a single free token

References

• Image source, citation and explanation:
  Newly Developed Telecommunication Services Nobuyoshi Terashima, in Intelligent Communication Systems, 2002, 7.6.5 Token Ring Protocol https://www.sciencedirect.com/topics/computer-science/token-ring

• IEEE standard 802.5

Also, this paper proposed a system with what I understood as multiple free tokens at once. You can take a look at it if you like:

R. Cohen and A. Segall, "Multiple logical token-rings in a single high-speed ring," in IEEE Transactions on Communications, vol. 42, no. 234, pp. 1712-1721, FEBRUARY/MARCH/APRIL 1994, doi: 10.1109/TCOMM.1994.582879. https://ieeexplore.ieee.org/document/582879