Multiple Access Protocol

Multiple access protocol is used to control/coordinate access to the link or link in a shared connection. It overcome the collision in shared channel. The type of Multiple access protocol: Channel partitioning protocol uses TDMA, FDMA and CDMA and Random Access Protocol uses ALOHA/ slotted ALOHA and CSMA/CA.

Summary

Multiple access protocol is used to control/coordinate access to the link or link in a shared connection. It overcome the collision in shared channel. The type of Multiple access protocol: Channel partitioning protocol uses TDMA, FDMA and CDMA and Random Access Protocol uses ALOHA/ slotted ALOHA and CSMA/CA.

Things to Remember

  1. Multiple access protocol is used to control/coordinate access to the link or link in a shared connection.
  2. All the nodes can transmit a frame at the same time which leads to a collision, to overcome this Multiple Access protocol is implemented.
  3. The type of Multiple access protocol: Channel partitioning protocol uses TDMA, FDMA and CDMA and Random Access Protocol uses ALOHA/ slotted ALOHA and CSMA/CA.

MCQs

No MCQs found.

Subjective Questions

Q1:

Explain the different methods of fedding baby with HIV positive mother ?


Type: Long Difficulty: Easy

Show/Hide Answer
Answer: <p><strong>Option 1: Exclusive breastfeeding with early weaning or when replacement feeds meet AFASS criteria.</strong></p>
<ul>
<li>Breastfeeding is stopped as soon as the baby can be weaned to a nutritionally adequate replacement food, which is AFASS (acceptable, feasible, affordable, sustainable and safe).</li>
<li>The baby receives only breast milk for a limited time until AFASS criteria are met or it becomes safe to give other foods (about 6 months).</li>
</ul>
<p><strong>Benefits:</strong></p>
<ul>
<li>Exclusive breastfeeding and early weaning by 6 months reduce the risk of HIV transmission.</li>
<li>The mother gives the baby all the benefits of breastfeeding during the critical early months of life ( best food for baby, protection from infection, supports best growth and development)</li>
<li>The risk of infection from use of a feeding bottle is avoided.</li>
</ul>
<p><strong>Risks and disadvantages:</strong></p>
<ul>
<li>Early weaning creates more work for the mother who must prepare a breast milk substitute.</li>
<li>Feeding with breast milk substitute is expensive.</li>
<li>Feeding with a breast milk substitute increases the baby&rsquo;s risk of other infections and poor situation.</li>
<li>Early weaning is difficult for both mother and baby. The mother&rsquo;s breast will be painfully engorged for a few days.</li>
<li>Early weaning may open the mother to criticism and stigma.</li>
<li>AFASS criteria may be difficult to meet.</li>
</ul>
<p><strong>Option 2: Expressing breast milk and Heat treating it before feeding</strong></p>
<ul>
<li>Heat treating kills HIV in breast milk.</li>
<li>The mother expresses her breast milk and heat treats it, then feeds it to baby to cup.</li>
</ul>
<p>Two methods used to heat treat breast milk are :</p>
<ul>
<li>Flash boiling: bring the milk just to boil, cool it, and feed it to the baby.</li>
<li>Holder ( orpretorial ) pasteurization
<ul>
<li>Place up to half a cup of breast milk in a clean glass jar and screw in the lid.</li>
<li>Fill a one liter aluminum pot half full with water and heat it to the boiling point.</li>
<li>When the water is boiling, remove the pot from the heat and immediately place of the jar of breast milk in the pot of hot water. Let the jar of breast milk stand in the hot water in 15 minutes.</li>
<li>Pasteurized milk can ve safely stored at room temperature for up to 12 hours if the jar is not opened or handled.</li>
</ul>
</li>
</ul>
<p><strong>Benefits:</strong></p>
<ul>
<li>There is almost no risk of transmitting HIV.</li>
<li>The baby gets nutritional benefits of breast milk. Although boiling destroys some properties of breast milk, it is still better for the newborn than formula prepared from animal milk.</li>
<li>The risk of infections less than from cup feeding than from bottle feeding</li>
</ul>
<p><strong>Risk or disadvantages:</strong></p>
<ul>
<li>The mother needs to spend a lot of time expressing breast milk, heat treat it, and cleaning the container and cup.</li>
<li>The mother must spend money on fuel to heat treat breast milk every day.</li>
<li>The baby must be stigmatized for not breast feeding directly.</li>
<li>There are cultural barriers to this practice in some countries.</li>
</ul>
<p><strong>Option 3: Wet nursing by a woman who is HIV negative </strong></p>
<p>The family finds a woman who tests HIV negative and is not likely to be exposed to future HIV infections to breastfeed the baby. The woman is given information on how to practice safe sex because the risk of transmission to the baby is very high if she becomes infected while breastfeeding.</p>
<p><strong>Benefits:</strong></p>
<ul>
<li>Breastfeeding by another woman gives the baby nearly all the same protective benefits as breastfeeding with the mother.</li>
<li>There is no risk of transmitting HIV though feeding, as long as the wet nurse dose not become infected.</li>
<li>The risk of infections from use of a feeding bottle is avoided.</li>
</ul>
<p><strong>Risk or disadvantages:</strong></p>
<ul>
<li>It may be difficult to be sure another person is HIV negative and stays negative.</li>
<li>The mother needs to spend focused time with her baby to her their relationship stay close.</li>
<li>It is not always easy to find a woman willing to take on the responsibility of wet nursing.</li>
<li>There are cultural barriers to this practice in some countries</li>
<li>The mother may be stigmatized for not nursing her own baby.</li>
<li>If the baby is born with HIV, there is a very small risk that breastfeeding may transmit the infection to the wet nurse has a cracked, bleeding nipple or other breast condition.</li>
<li>If the mother does not breastfeed, she looses the child spacing benefits of breastfeeding.</li>
</ul>
<p><strong>Option 4: Replacement feeding with commercial infant formula.</strong></p>
<p>The infant is fed commercial infant formula from birth (no breastfeeding).</p>
<p><strong>Option 5: Replacement feeding with home modified animal milk</strong></p>
<p>The infant is fed appropriately modified animal milk from birth (no breastfeeding)</p>
<p><strong>Benefits of replacement feeding:</strong></p>
<ul>
<li>No risk of HIV transmission through feeding (There is still a chance that the baby may have acquired HIV infection during pregnancy or birth)</li>
<li>Other people besides the mother can help feed the baby.</li>
<li>Mother and baby can separated. Infant feeding is not interrupted of the mother is sick or dies.</li>
<li>The baby can become closely attached to other people besides the mother.</li>
</ul>
<p><strong>Risks and disadvantages:</strong></p>
<ul>
<li>Safe replacement feeding requires:
<ul>
<li>A reliable and affordable supply of the selected replacement food and safe place to store it.</li>
<li>Nutritionally adequate commercial infant formula or home modified animal milk.</li>
<li>Clean water to prepare the replacement food.</li>
<li>Adequate supply or fuel.</li>
<li>Good hygiene and good situation.</li>
<li>Time to prepare and feed the infant the replacement food.</li>
<li>Knowledge of how to correctly modify animal milk, or the ability to read instructions on the selected infant formula package.</li>
</ul>
</li>
<li>Breast milk substitute lack anti infective antibodies.</li>
<li>Breast milk substitutes lack of growth hormone.</li>
<li>Purchase of enough breast milk substitute to feed an infant can consume a large portion of the family&rsquo;s income.</li>
<li>Improper preparation of breast milk substitutes can cause diarrheal disease and/ or malnutrition.</li>
<li>Women who do not breastfeed lose the child spacing benefit of breastfeeding and need access to affordable and appropriate family planning services.</li>
<li>Infants who do not breastfeed may not got adequate psychosocial stimulation and may not bond well with their mothers.</li>
<li>Where breastfeeding is the norm, women who do not breastfeed may be stigmatized and marginalized.</li>
</ul>

Videos

No videos found.

Multiple Access Protocol

Multiple Access Protocol

Multiple Access Protocol

Multiple access protocol is used to control/coordinate access to the link or link in a shared connection. Nodes can regulate their transmission within the shared broadcast channel by using Multiple Access Protocol. All the nodes can transmit a frame at the same time. This may arise to the collision, so to overcome this Multiple Access protocol is implemented.

Fig: Types of Multiple Access Protocol
Fig: Types of Multiple Access Protocol


Channel partitioning protocol uses TDMA, FDMA and CDMA where TDMA shares the channel according to time slots, FDMA share channel in different frequency range and CDMA divide the channel by providing unique codes.
Random Access Protocol uses ALOHA/ slotted ALOHA and CSMA/CA.

Reference

  1. Tanenbaum, WetherRall, Andrew S. , David J. ,Computer Networks. 5th Ed. Boston: Pearson Education, Inc
  2. W. Stallings, “Data and Computer Communication”, Macmillan Press, 1989.

Lesson

Data Link Layer

Subject

Computer Engineering

Grade

Engineering

Recent Notes

No recent notes.

Related Notes

No related notes.