23
At these lower speeds , ATM provides a useful ability to carry multiple logical circuits on a single physical or virtual medium , although other techniques exist , such as Multi-link PPP and Ethernet VLANs , which are optional in VDSL implementations .
 None
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 None