QoS Improvement Using In-Network Caching Based on Clustering and Popularity Heuristics in CCN

. 2021 Oct 29;21(21):7204. doi: 10.3390/s21217204

Algorithm 3: Content message forwarding and caching mechanism

(U_{u}, D_{j}, R_{m} / s e r v, R_{y})

If requested content exists in the $C S (R_{m})$ or $I_{j}$ reaches the server $(s e r v)$ , then following steps are performed:
- (a)
  Prepare a Content message $D_{j}$ with initializing corresponding field $N a m e (D_{j})$ and the requested payload.
- (b)
  Replicate the values of $C l u s (I_{j})$ and $H (I_{j})$ fields from $I_{j}$ to the $C l u s (I_{j})$ and $H (I_{j})$ fields of $D_{j}$ .
- (c)
  Initialize, $H (D_{j}) = 0$ .
- (d)
  The content provider $(R_{m} / s e r v)$ writes its unique cluster identification id $(C l u s (R_{m}) / C l u s (S e r v)$ in the $C l u s (D_{j})$ field of $D_{j}$ .
- (e)
  Initialize the boolean field $η$ as TRUE.
- (f)
  Transmit $D_{j}$ towards $U_{u}$ .
When $D_{j}$ reaches to an intermediate router $R_{y}$ , then $R_{y}$ perform following steps for caching decisions and content forwarding towards $U_{u}$ .
Update the value in $H (D_{j})$ field as $H (D_{j})$ = $H (D_{j}) + 1$ .
If $C l u s (I_{j}) \neq C l u s (R_{y})$ or $C l u s (I_{j}) = C l u s (D_{j})$ , then move to $s t e p$ -6.
Else,
- (a)
  Compute, $P T_{R_{y}} (N a m e (D_{j})$ in $P T_{R_{y}}$ .
- (b)
  Compute, $C a c h i n g_G a i n = P T_{R_{y}} (N a m e (D_{j})) \times \frac{H (D_{j})}{H (I_{j})}$
- (c)
  If $T_{R} \leq C a c h i n g_G a i n$ and $η = T R U E$ then,
  - Cache $D_{j}$ in the $C S (R_{y})$ using LFU cache replacement strategy.
  - Reset $η = F A L S E$ .
$R_{y}$ forwards $D_{j}$ towards the $U_{u}$ using its PIT.