While creating the pppoe connection, there is no option for specifying the future name of ppp-device - they are created as ppp0, ppp1, etc.

But pppd package does have such an option - "unit <num> - sets the ppp unit number (for a ppp0 or ppp1 etc interface name) or outbound  connections". This is very useful in such situations as iptables rules with interface options in multi-pppoe evironment.

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Instead, option for assigning any arbitrary interface name will be more suitable. Or in other hand, possibility to append any custom pppd options.